问答题Green Gene Technology For the past 10,000 years humans have influenced the plants they use at first unknowingly, later by design. Today’s crops have been created by a process of selection and classical breeding. More specific improvements in breeding will be possible in future. Science has cracked the genetic information code. Green gene technology is an effective tool in crop breeding, enabling us to develop new crops even more rapidly and specifically. We can make them more efficient, optimizing their contents and valuable substances to suit the wishes and requirements of customers and the processing industry. Their metabolism can be individually modified, making them produce starch, protein and fats with special properties. Through gene transfer plants can be made more resistant to viruses, bacteria, harmful fungi and insect pests. Genetically modified plants can be cultivated to possess improved stress behavior, with the result that they absorb water better in dry locations and can make more efficient use of soil nutrients. We can also optimize weed control. To do so, we make crops tolerant to environmentally sound and easily degradable herbicides. This is not as simple as it sounds. But we have been successful: Innovator has been on the Canadian market since 1995. This is the first oilseed rape variety to contain the glufosinate tolerance gene, facilitating the use of AgrEvo’s broad-spectrum herbicide liberty. We are committed to green gene technology, with which we aim to make crop breeding even more efficient and environmentally friendly. Before being brought on to the market these genetically modified plants are researched and tested for years until the questions posed regarding their safety have been answered. This is a great opportunity for us to realize our vision: the use of faster methods to breed varieties which will continue to provide us with sufficient food and raw materials in future. Our fossil reserves will soon be exhausted. Experts estimate that we only have enough oil for another 43 years and natural gas for less than 60. This means we must rethink and act accordingly, using new crop varieties to step up the move to replenishable sources of raw materials and energy. In other words, green gene technology is the key technology for sustainable agriculture.
问答题
Green Gene Technology For the past 10,000 years humans have influenced the plants they use at first unknowingly, later by design. Today’s crops have been created by a process of selection and classical breeding. More specific improvements in breeding will be possible in future. Science has cracked the genetic information code. Green gene technology is an effective tool in crop breeding, enabling us to develop new crops even more rapidly and specifically. We can make them more efficient, optimizing their contents and valuable substances to suit the wishes and requirements of customers and the processing industry. Their metabolism can be individually modified, making them produce starch, protein and fats with special properties. Through gene transfer plants can be made more resistant to viruses, bacteria, harmful fungi and insect pests. Genetically modified plants can be cultivated to possess improved stress behavior, with the result that they absorb water better in dry locations and can make more efficient use of soil nutrients. We can also optimize weed control. To do so, we make crops tolerant to environmentally sound and easily degradable herbicides. This is not as simple as it sounds. But we have been successful: Innovator has been on the Canadian market since 1995. This is the first oilseed rape variety to contain the glufosinate tolerance gene, facilitating the use of AgrEvo’s broad-spectrum herbicide liberty. We are committed to green gene technology, with which we aim to make crop breeding even more efficient and environmentally friendly. Before being brought on to the market these genetically modified plants are researched and tested for years until the questions posed regarding their safety have been answered. This is a great opportunity for us to realize our vision: the use of faster methods to breed varieties which will continue to provide us with sufficient food and raw materials in future. Our fossil reserves will soon be exhausted. Experts estimate that we only have enough oil for another 43 years and natural gas for less than 60. This means we must rethink and act accordingly, using new crop varieties to step up the move to replenishable sources of raw materials and energy. In other words, green gene technology is the key technology for sustainable agriculture.
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EA rainforest is an area covered by tall trees with the total high rainfall spreading quite equally through the year and the temperature rarely dipping below l6℃．Rainforests have a great effect on the world environment because they can take in heat from the sun and adjust the climate．Without the forest cover，these areas would reflect more heat into the atmosphere，warming the rest of the world. Losing the rainforests may also influence wind and rainfall patterns，potentially causing certain natural disasters all over the world．In the past hundred years，humans have begun destroying rainforests in search of three major resources(资源)：land for crops，wood for paper and other products，land for raising farm animals．This action affects the environment as a whole．For example，a lot of carbon dioxide (二氧化碳)in the air comes from burning the rainforests．People obviously have a need for the resources we gain from cutting trees but we will suffer much more than we will benefit.There are two main reasons for this．Firstly，when people cut down trees，generally they can only use the land for a year or two．Secondly，cutting large sections of rainforests may provide a good supply of wood right now，but in the long run it actually reduces the world’s wood supply．Rainforests are often called the world’s drug store．More than 25％ of the medicines we use today come from plants in rainforests．However，fewer than l％of rainforest plants have been examined for their medical value．It is extremely likely that our best chance to cure diseases lies somewhere in the world’s shrinking rainforests．72．Rainforests can help to adjust the climate because they ．A．reflect more heat into the atmosphereB．bring about high rainfall throughout the worldC．rarely cause the temperature to drop lower than l6℃D．reduce the effect of heat from the sun on the earth
Working hours in the United States ____________over the past 20 years.A. have increasedB. increasedC. were increasingD. have been increased
John and I ______ friends for eight years. We first went to know each other at a Christmas party. But we ______ each other a couple of times before that. A had been; have seenB have been; have seenC had been; had seenD have been; had seen
共用题干第一篇Putting Plants to WorkUsing the power of the sun is nothing new.People have had solar-powered calculators and buildings withsolar panels（太阳能电池板）for decades. But plants are the real experts. They' ve been using sunlight as anenergy source for billions of years.Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide（二氧化 碳）,and water into sugarsand starche（淀粉）,stored energy that the piants can use. This conversion process is called photosynthesis (光合作用）Unfortunately, unless you' re a plant, it's difficult and expensive to convert sunlight into storable energy. That's why scientists are taking a closer look at exactly how plants do it.Some scientists are trying to get plants,or biological cells that act like plants, to work as very small photosynthesic power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in Golden. Cobo.,is working with green algae（水藻）.She's trying to trick them into producing hydrogen instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficient- ly ,the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthe- sis , plants normally make sugars or strchds. "But under certain conditions,a lot of algae are able to use the sunlight energy not to store starch , but to make hydrogen."Ghirardi says. For example ,algae will produce hy-drogen in an airfree environment. It' s the oxygen in the air that prevents algae from making hydrogen most of the time.Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate（硫酸盐） from the environment that the algae grow in, they will make hydrogen instead of sugars,even when air is present.Unfortunately, removing the sulfate also makes the algae's cells work very slowly,and not much hydrogen is produced. Still ,the researchers see this as a first step in their goal to produce hydrogen efficiently from algae. With more work,they may be able to speed the cells' activity and produce larger quantities of hydrogen.The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to get and to feed, Ghirardi says,and they can grow almost anywhere:"You can grow them in a reactor, in a pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms." How do plants relate to solar energy?A: They have been using it for billions of years.B: They are the real experts in producing it.C: They have been a source of it.D: They have been used to produce it.
共用题干第一篇Human EvolutionBeing a man has always been dangerous.There are about 105 males born for every 100 females, but this ratio drops to near balance at the age of maturity,and among 70-year-old there are twice as many women as men. But the great universal of male mortality is being changed.Now,boy babies survive almost as well as girls do. This means that,for the first time,there will be an excess of boys in those crucial years when they are searching for a mate. More important,another chance for natural selection has been removed. Fifty years ago,the chance of a baby(particularly a boy baby)surviving depended on its weight. A kilogram too light or too heavy meant almost certain death.Today it makes almost no difference.Since much of the variation is due to genes,one more agent of evolution has gone.There is another way to commit evolutionary suicide:stay alive,but have fewer children.Few people are as fertile as in the past. Except in some religious communities,very few women have 15 children.Nowadays the number of births,like the age of death,has become average.Most of us have roughly the same number of offspring. Again,differences between people and the opportunity for natural selection to take advantage of it have diminished.India shows what is happening. The country offers wealth for a few in the great cities and poverty for the remaining tribal peoples.The grand mediocrity of today一everyone being the same in survival and number of offspring means that natural selection has lost 80%of its power in upper-middle一class India compared to the tribes.For us,this means that evolution is over;the biological Utopia has arrived.Strangely,it has involved little physical change.No other species fills so many places in nature.But in the past 100,000 years一even the past 100 years一our lives have been transformed but our bodies have not. We did not evolve,because machines and society did it for us.Darwin had a phrase to describe those ignorant of evolution:"they look at an organic being as savage looks at a ship,as at something wholly beyond his comprehension."No doubt we will remember a 20th century way of life beyond comprehension for its ugliness. But however amazed our descendants may be at how far from Utopia we were,they will look just like us.What used to be the danger in being a man according to the first paragraph?A:A lack of mates.B:A fierce competition.C:A lower survival rate.D:A defective gene.
共用题干Using HIV Virus to Cure CancerScientists are planning to use human immuno deficiency（免疫缺陷）virus(HIV) , one of mankind's most feared viruses,as a carrier of genes which can fight cancer and a range of diseases that cannot be cured.The experts say HIV has an almost perfect ability to avoid the body's immune（免疫的）defenses, making it ideal for carrying replacement genes into patients'bodies,according to the Observer.A team at the California-based Salk Institute,one of the world's leading research centers on biological sciences,has created a special new breed of HIV and has started negotiations with the U.S.Food and Drug Administration(FDA)to begin clinical gene therapy（治疗）trials this year.The first trials are expected to involve patients suffering from cancers that cannot be cured by surgery although project leader Professor Inder Verma said the HIV technique would have“far wider applications”.The plan remains very likely to cause controversy since it involves making use of a viruswhich has caused more than 22 million deaths around the world in the past two decades.Verma said that the idea of using HIV for a beneficial purpose was“shocking”but the fierce nature of HIV had disappeared by having all six of the potentially deadly genes removed.Illnesses such as various cancers are caused when a gene in a patient's body fails to work properly.In the past two years, breakthroughs in genetics（遗传学）have led gene therapy sci-entists to try and replace the genes that do not function normally.Unfortunately,the body's immune defenses have been known to attack the modified genes and make them lose their effects before they can start their task and progress in the field has been held up by the lack of a suitable carrier.The HIV virus has the ability to escape from,and then destroy,the immune defense cells designed to protect our bodies and this makes it attractive to scientists as a way of secretly conveying replacement genes into patients'bodies.The HIV virus has caused more deaths in developed countries.A:RightB:WrongC:Not mentioned
共用题干Using HIV Virus to Cure CancerScientists are planning to use human immuno deficiency（免疫缺陷）virus(HIV) , one of mankind's most feared viruses,as a carrier of genes which can fight cancer and a range of diseases that cannot be cured.The experts say HIV has an almost perfect ability to avoid the body's immune（免疫的）defenses, making it ideal for carrying replacement genes into patients'bodies,according to the Observer.A team at the California-based Salk Institute,one of the world's leading research centers on biological sciences,has created a special new breed of HIV and has started negotiations with the U.S.Food and Drug Administration(FDA)to begin clinical gene therapy（治疗）trials this year.The first trials are expected to involve patients suffering from cancers that cannot be cured by surgery although project leader Professor Inder Verma said the HIV technique would have“far wider applications”.The plan remains very likely to cause controversy since it involves making use of a viruswhich has caused more than 22 million deaths around the world in the past two decades.Verma said that the idea of using HIV for a beneficial purpose was“shocking”but the fierce nature of HIV had disappeared by having all six of the potentially deadly genes removed.Illnesses such as various cancers are caused when a gene in a patient's body fails to work properly.In the past two years, breakthroughs in genetics（遗传学）have led gene therapy sci-entists to try and replace the genes that do not function normally.Unfortunately,the body's immune defenses have been known to attack the modified genes and make them lose their effects before they can start their task and progress in the field has been held up by the lack of a suitable carrier.The HIV virus has the ability to escape from,and then destroy,the immune defense cells designed to protect our bodies and this makes it attractive to scientists as a way of secretly conveying replacement genes into patients'bodies.HIV can be safely used to cure cancer only if the deadly genes have been removed.A:RightB:WrongC:Not mentioned
共用题干Using HIV Virus to Cure CancerScientists are planning to use human immuno deficiency（免疫缺陷）virus(HIV) , one of mankind's most feared viruses,as a carrier of genes which can fight cancer and a range of diseases that cannot be cured.The experts say HIV has an almost perfect ability to avoid the body's immune（免疫的）defenses, making it ideal for carrying replacement genes into patients'bodies,according to the Observer.A team at the California-based Salk Institute,one of the world's leading research centers on biological sciences,has created a special new breed of HIV and has started negotiations with the U.S.Food and Drug Administration(FDA)to begin clinical gene therapy（治疗）trials this year.The first trials are expected to involve patients suffering from cancers that cannot be cured by surgery although project leader Professor Inder Verma said the HIV technique would have“far wider applications”.The plan remains very likely to cause controversy since it involves making use of a viruswhich has caused more than 22 million deaths around the world in the past two decades.Verma said that the idea of using HIV for a beneficial purpose was“shocking”but the fierce nature of HIV had disappeared by having all six of the potentially deadly genes removed.Illnesses such as various cancers are caused when a gene in a patient's body fails to work properly.In the past two years, breakthroughs in genetics（遗传学）have led gene therapy sci-entists to try and replace the genes that do not function normally.Unfortunately,the body's immune defenses have been known to attack the modified genes and make them lose their effects before they can start their task and progress in the field has been held up by the lack of a suitable carrier.The HIV virus has the ability to escape from,and then destroy,the immune defense cells designed to protect our bodies and this makes it attractive to scientists as a way of secretly conveying replacement genes into patients'bodies.FDA has approved the plan of using HIV to cure cancer in humans.A:RightB:WrongC:Not mentioned
共用题干“Salty” Rice Plant Boosts HarvestsBritish scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world. The attitude of the author towards the research project is______.A: positiveB: negativeC: suspiciousD: indifferent
During the past ten years there have been dramatic changes in the international situation.A: permanentB: powerfulC: strikingD: practical
共用题干“Salty” Rice Plant Boosts HarvestsBritish scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world. Flowers and Yeo have started a program______.A: to find ways to prevent water pollutionB: to identify genes that promote growth in salty soilC: to breed rice plants that taste saltyD: to find ways to remove excessive salt from soil
共用题干“Salty” Rice Plant Boosts HarvestsBritish scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world. Which of the following is NOT mentioned as a cause of the problem discussed in the passage?A: Natural barriers to sea water have been destroyed.B: The water table has gone down after droughts.C: Sea level has been continuously rising.D: Evaporation of water leaves salt behind.
共用题干“Salty” Rice Plant Boosts HarvestsBritish scientists are breeding a new generation of rice plants that will be able to grow in soil containing salt water. Their work may enable abandoned farms to become productive once more.Tim Flowers and Tony Yeo,from Sussex University's School of Biological Sciences,have spent several years researching how crops,such as rice,could be made to grow in water that has become salty.The pair have recently begun a three-year programme,funded by the Biotechnology and Biological Sciences Research Council,to establish which genes enable some plants to survive salty conditions. The aim is to breed this capability into crops,starting with rice.It is estimated that each year more than 10m hectares（公顷）of agricultural land are lost because salt gets into the soil and stunts（妨碍生长）plants. The problem is caused by several factors. In the tropics , mangroves（红树林）that create swamps（沼泽）and traditionally formed barriers to sea water have been cut down .In the Mediterranean,a series of droughts have caused the water table to drop,allowing sea water to seep（渗透）in. In Latin America , irrigation often causes problems when water is evaporated（蒸发）by the heat , leaving salt deposits behind.Excess salt then enters the plants and prevents them functioning normally.Heavy concentrations of minerals in the plants stop them drawing up the water they need to survive.To overcome these problems,Flowers and Yeo decided to breed rice plants that take in very little salt and store what they do absorb in cells that do not affect the plants' growth.They have started to breed these characteristics into a new rice crop,but it will take about eight harvests before the resulting seeds are ready to be considered for commercial use.Once the characteristics for surviving salty soil are known,Flowers and Yeo will try to breed the appropriate genes into all manners of crops and plants.Land that has been abandoned to na- ture will then be able to bloom again,providing much needed food in the poorer countries of the world. Which of the following statements about Flowers and Yeo is true?A: They are students at Sussex University.B: They are rice breeders.C: They are husband and wife.D: They are colleagues at an institution of higher learning.
At the first sight the planet Mars does not appear very welcome to any kind of life．It has very little oxygen and water,the temperature at night is below-50~Cand winds of 100 miles per hour cause severe dust storms．However,the surface of the planet seems to show that water flowed across it some time in the past,and it is believed that there is enough ice at the poles to cover the planet with water if it melts．Although there is no life on the Mars now,some scientists think that there may have been some form of life long time ago．At that time,the planet had active volcanoes;the atmosphere was thicker and warmer;and there was water．In fact,in some ways the Mars may have been similar to the Earth,where life exists.Some people believe that the Mars could support life in the future if the right conditions were produced．The first step would be to warm the planet using certain gases which trap the Sun's heat in the planet's atmosphere．With warmth,water and carbon dioxide(二氧化碳),simple plants could begin to grow．These plants could slowly make the Mars more suitable for living．It is estimated that the whole process might take between 100,000 and 200,000 years．In the meantime,people could begin to live on the planet in special closed environments．They would provide a lot of useful information about conditions on the Mars and the problems connected with living there.Some scientists think there may have been life on the Mars in the past because__.A.there is no life there nowB.there is a large amount of water at the polesC.the Mars may be able to support life in the futureD.conditions may have been similar to those on the Earth
Text 1 In an essay entitled“Making It in America”,the author Adam Davidson relates a joke from cotton country about just how much a modern textile mill has been automated:The average mill has only two employees today,“a man and a dog.The man is there to feed the dog,and the dog is there to keep the man away from the machines.”Davidson's article is one of a number of pieces that have recently appeared making the point that the reason we have such stubbornly high unemployment and declining middleclass incomes today is also because of the advances in both globalization and the information technology revolution,which are more rapidly than ever replacing labor with machines or foreign worker.In the past,workers with average skills,doing an average job，could earn an average lifestyle.But，today，average is officially over.Being average just won't earn you what it used to.It can't when so many more employers have so much more access to so much more above average cheap foreign labor,cheap robotics,cheap software,cheap automation and cheap genius.Therefore,everyone needs to find their extra—their unique value contribution that makes them stand out in whatever is their field of employment.Yes,new technology has been eating jobs forever,and always will.But there's been acceleration.As Davidson notes,“In the 10 years ending in 2009,U.S.factories shed workers so fast that they erased almost all the gains of the previous 70 years;roughly one out of every three manufacturing jobs—about 6 million in total—disappeared.”There will always be change—new jobs,new products,new services.But the one thing we know for sure is that with each advance in globalization and the I.T.revolution,the best jobs will require workers to have more and better education to make themselves above average.In a world where average is officially over,there are many things we need to do to support employment,but nothing would be more important than passing some kind of G.I.Bill for the 21st century that ensures that every American has access to posthigh school education.The quotation in Paragraph 4 explains that_____A.gains of technology have been erasedB.job opportunities are disappearing at a high speedC.factories are making much less money than beforeD.new jobs and services have been offered
共用题干What Can Gene Technology BringAmong all the fast growing science and technology,the research of human genes,or biological engineering as people call it,is drawing more and more attention now,Sometimes it is a hot topic discussed by people.The greatest thing that gene technology can do is to cure some serious diseases.Doctors at present can almost do nothing with them.Cancer and heart disease are the examples.______________(46)And to date,doctors have not found an effective way to cure them.But if the gene technology is applied, these two diseases can be cured completely,bringing happiness and more living days to the patients._____________(47)Gene technology can help people to give birth to more healthy and clever children.Some families,withthe English imperial family being a good example , have hereditary（遗传的）diseases._____________ (48 ) Thisis a great trouble for these families.In the past,doctors could do nothing about the hereditary diseases.Butgene technology can solve this problem perfectly.______________(49)Some people are worrying that the gene research can be used to manufacture human beings in large quantities.In the past few years,scientists have succeeded in cloning a sheep,so these people predict that human babies would soon be cloned._____________(50)Of course,the governments must take care to controlgene technology._________（47）A:Every year,millions of people are murdered by these two diseases.B:But I believe cloned babies will not come out in large quantities,for most couples in the world can havebabies in very normal way.B:This means their children will for sure have the family disease.C:The scientists just need to find the wrong gene and correct it,and a healthy child will be born.E:In addition,the great amount of money people spend on curing their diseases can be saved,and it benefitst he economy as well.F:Clone technology is an achievement in science.
Which two options does Cisco PfR use to control the entrance link selection with inbound optimization？（）A、Prepend extra AS hops to the BGP prefix.B、Advertise more specific BGP prefixes（longer mask）.C、Add（prepend）one or more communities to the prefix that is advertised by BGP.D、Have BGP dampen the prefix.
Using Oracle Scheduler you have scheduled two jobs， JOB_Aand JOB_B， to run at 9：00 p.m. every Friday. You want both the jobs to use a single resource plan， WEEKEND_PLAN. Which task must have already been performed to enable you to achieve this objective？（）A、 A window must have been created with the WEEKEND_PLAN resource plan.B、 A program must have been created with the WEEKEND_PLAN resource plan.C、 A job class must have been created with the WEEKEND_PLAN resource plan.D、 A window group must have been created with the WEEKEND_PLAN resource plan.
单选题We may infer from the fourth paragraph that ______.Ahumans have been growing food crops more than ten thousand years.Bhumans have learned how to produce biofuels for a long time.Chumans are just on the beginning of making biofuels.Da cell wall includes four hemicellulose.
问答题Practice 1 Genetic researchers have accelerated a plant’s growth by making its cells split faster—a technique that could someday lead to healthier crops, shorter growing seasons and less use of herbicides. One outside scientist called the findings astonishing. But the technique needs more testing on a range of plants, and public fear of genetically modified food is jeopardizing support for such experiments, especially in Europe, researchers said. The experiment, reported Thursday in the journal Nature, was carried out by a team at Cambridge University. The researchers first took a gene promoting cell division from inside the Arabidopsis plant, a flowering weed often used for genetic experiments. They transplanted that gene into a tobacco plant. There, in an especially potent form, the gene produced large amounts of a protein that, in combination with other chemicals naturally in the tobacco, made the plant’s cells divide more quickly at the tips of roots and shoots. Within a month after planting, the altered tobacco grew as much as twice as tall as other tobacco plants. Ultimately, the other plants caught up, and both groups then appeared identical in all ways. “It’s sort of like they’ve been able to make the plant go full throttle,” a said plant growth biologist John Schiefelbein at the University of Michigan. The leader of the study, Claire Cockcroft, said it is conceivable that the technique could be transferred to other species. Such plants, which probably would take years to develop commercially, might allow an extra planting in some climates or the introduction of crops in places where the growing season is too short, researchers said. The quick-growth plants would presumably take hold more easily, requiring less chemical herbicide to knock out weeds. Such plants might make easier and cheaper sources of some drugs. In scientific circles, the British research may also help settle an intense debate over what makes plants grow. Some argue, like these researchers, that something at the cellular level switches on growth; others look to hormones or other chemicals at a higher level of the plant’s makeup. “This is astonishing. Normally you would expect growth regulation to be more complicated,” said plant researcher Xuemin Wang at Kansas State University. “This has huge implications in terms of how we look at plant growth.” Biotechnology companies have genetically manipulated fruits and vegetables to make them more attractive or resistant to insects and disease. Genetic work has shown some early promise for faster growth, too. But previous attempts to boost growth through faster cell division have produced more cells—but smaller ones—and no overall growth. Scientists said such work is safe, with little chance of accidentally turning an unwanted plant into a fast-growing weed. After all, crops have been selectively bred for decades to bring out certain traits. However, ethicist Jeffrey Burkhardt at the University of Florida’s Institute of Food and Agricultural Sciences said selective breeding takes perhaps 15 years, giving scientists ample time to see the implications. “With the new biotechnology, you’re potentially moving traits in and out within a year,” he said.
单选题Why switch grass and Miscanthus were taken as energy plant?ABecause they contain more cellulose.BBecause genomes have been sequenced for clues to make other plants better energy crops.CBecause some scientists are breeding a wide variety o[Candidate crops.DBecause the spotlight is on this underdeveloped field.
单选题These classical works have been simplified on behalf of beginners of English.Aas the representative ofBin the interest ofCin the name ofDin the process of
单选题Once more I have to leave Beijing, _____ I have been living for eight years.AthatBwhereCwhichDas
单选题By saying “raw materials do not exist, they are created” the author means _____.Athat there will be no more raw materials on the earth some time later, and man will have to create materials by themselvesBthat it is use that makes raw materials valuableCthat people have created various useful materials by using their intelligence and wisdomDhuman creativity is amazing
单选题During the past ten years, there have been_____changes in the country.AlastingBdramaticCpowerfulDimaginary
问答题Practice 2 Transgenic plants and animals result from genetic engineering experiments in which genetic material is moved from one organism to another, so that the latter will exhibit a characteristic. Business corporations, scientists, and farmers hope that transgenic techniques will allow more cost-effective and precise plants and animals with desirable characteristics that are not available using up to date breeding technology. Transgenic techniques allow genetic material to be transferred between completely unrelated organisms. In order for a transgenic technique to work, the genetic engineer must first construct a transgene, which is the gene to be introduced plus a control sequence. When making a transgene, scientists usually substitute the original promoter sequence with one that will be active in the correct tissues of the recipient plant or animal. The creation of transgenic animals is one of the most dramatic advances derived from recombinant DNA technology. A transgenic animal results from insertion of a foreign gene into an embryo. The foreign gene becomes a permanent part of the host animals’ genetic material. As the embryo develops, the foreign gene may be present in many cells of the body, including the germ cells of the testis or the ovary. If the transgenic animal is fertile, the inserted foreign gene (transgene) will be inherited by future progeny. Thus, a transgenic animal, once created, can persist into future generations. Transgenic animals are different from animals in which foreign cells or foreign organs have been engrafted. The progeny of engrafted animals do not inherit the experimental change. The progeny of transgenic animals do. The techniques for creating a transgenic animal include the following: 1) picking a foreign gene, 2) placing the foreign gene in a suitable form called a “construct” which guides the insertion of the foreign gene into the animal genome and encourages its expression, and 3) injecting the construct into a single fertilized egg or at the very early embryo stage of the host animal. Much genetic engineering goes into the choice of a foreign gene and building a construct. The construct must have promoters to turn on foreign gene expression at its new site within the host animal genome. By choosing a particular promoter and splicing it in front of the foreign gene, we can encourage expression of our transgene within a specific tissue. One of the most important applications of transgenic animals is the development of new animal models of human disease. Transgenic animals can serve as models for many malignant tumors. Mice have been the most frequent hosts for transgenic modification, other domestic animals have also been used. One idea has been to create transgenic cows which secrete important pharmaceutical substances in their milk. Other attempts are being made to express human interferon in the milk of sheep. A transgenic crop plant contains a gene or genes which have been artificially inserted instead of the plant acquiring them through pollination. The inserted gene sequence (known as the transgene) may come from another unrelated plant, or from a completely different species: transgenic BT corn, for example, which produces its own insecticide, containing a gene from a bacterium. Plants containing transgenes are often called genetically modified or GM crops although in reality all crops have been genetically modified from their original wild state by domestication, selection and controlled breeding over long periods of time.
单选题The examples given in Para.2 are used to illustrate that ______.Apeople’s handwriting would have been better without computersBartists are those who like new technology for its own sakeCtechnical improvements enable tennis players to defeat their opponentsDpeople rely too much on modern technology