单选题Such problem ()air, water, and noise pollutions are becoming more and more serious in some big cities.AlikeBasCofDabout

单选题
Such problem ()air, water, and noise pollutions are becoming more and more serious in some big cities.
A

like

B

as

C

of

D

about


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In Leon Nacson’s view, air and water are our Number One priorities for the following reasons except ().A、he cannot understand why people are polluting air and waterB、there will definitely be no fresh air and clean water for future generationsC、we would run out of air and water if we didn’t stop polluting themD、air and water polluting are the current and futu

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共用题干第三篇Preserve the EnvironmentThroughout history man has changed his physical environment in order to improve his way of life.With the tools of technology he has altered many physical features of the earth.He has transformed woodlands into farmland,and made lakes and reservoirs out of rivers for irrigation purposes or hydroelectric power. Man has also modified the face of the earth by draining marshes and cutting through mountains tobuild roads and railways.However,man's changes to the physical environment have not always had beneficial results.Today, pollution of the air and water is an increasing danger to the health of the planet.Each day thousands of tons of gases come out of the exhausts of motor vehicles;smoke from factories pollutes the air of industrialized areas and the surrounding areas of countryside.The air in cities is becoming increasingly unhealthy.The pollution of water is equally harmful.In the sea,pollution from oil is increasing and is killing enor- mous numbers of algae(水藻),fish and birds.The whole ecological balance of the sea is being changed. The same problem exists in rivers.Industrial wastes have already made many rivers lifeless.Conservationists believe that it is now necessary for man to limit the growth of technology in order to sur-vive on earth.According to the passage,pollution of the air and water is caused by__________.A:thousands of tons of gases coming out of the exhausts of motor vehiclesB:the changes of the environment that technology has brought to manC:the increasing amount of oil that has been producedD:industrial wastes discharged into rivers

Such problem ()air, water, and noise pollutions are becoming more and more serious in some big cities.AlikeBasCofDabout

The modes of transportation include()。A、rail and road transportB、water transportC、pipelinesD、air transport

While working in the server room a technician notices that water is forming on the walls of the serverroom. Which of the following is the BEST course of action to correct the problem?()A、 Contact facilities staff to adjust the humidity levels.B、 Leave the temperature the same, after time it will evaporate on its own.C、 Lower the temperature, the cold air will help the water evaporate.D、 Contact facilities staff to raise the temperature of the room.

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单选题For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of the listed conditions should remain constant regardless of load changes?()AChilled water system supply temperatureBChilled water system return temperatureCCompressor discharge temperatureDCompressor suction pressure

单选题请阅读 Passage 1,完成第 21~25小题。Passage 1These days,many large city buildings are equipped with their own air-conditioning systems.These systems help keep the buildings cool,but they can also damage the environment.Since they use a lot of electricity,for instance,they contribute indirectly to global warming.In addition,the water that flows through the systems is often cooled using chemicals called chlorofluorocarbons,or CFCs,that are believed to damage the Earth's ozone layer.Recently,though,a system has been built in the city of Toronto,Canada,that cools buildings with little damage to the environment. In the traditional air-conditioning systems found in most large buildings,water is pumped through the building in a continuous cycle.The water is first cooled to a temperature of 4℃ in machines called chillers.It is then sent to individual units that cool the air in each room.As the water flows through the building,it gradually becomes warmer.Finally,it reaches the roof ,where it is left to cool down naturally in a water tower.After that it is returned to the chillers,where the cycle begins again.Toronto lies on the shore of Lake Ontario,one of North America's Great Lakes,and the new system makes use of cold water taken from about 80 meters below the surface of the lake.At this depth,the water in the lake remains at 4℃ all year round.This is exactly the temperature to which the water in air-conditioning systems is cooled.However,the water from the lake is not pumped directly into the air-conditioning systems.Instead,it is used to cool the water that is already inside the air-conditioning systems.After that,the lake water is added to the city's ordinary water supply.Enwave,the company that developed this deep-lake cooling system,says that it uses 75 percent less energy than traditional air conditioning.And since no CFCs are used,no damage can be caused to the ozone layer.Not every city is located next to a large lake,but experts believe that systems like the one being used in Toronto could be built elsewhere by using other natural sources of cold water.What is the function of the chillers in a traditional air-conditioning system?AThey pump the air continuously to the units in each room.BThey lower the temperature of the water in the system.CThey help the water cool down naturally on the roof .DThey gradually clean the water as it flows through the building.

单选题As the air passes through the charge air cooler, its temperature may be reduced and moisture condensed, with the condensate in danger of being carried into the engineSo a water separator should be mounted beneath the bottom part of the engine inlet manifoldA water separator is used in order to ().Akeep the air from being carried into the engineBkeep the moisture from being condensedCkeep the danger from being carded into the engineDtake away the condensate from the air

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单选题In a vacuum boiling evaporator, the fresh water generated is pumped out by ().Aa brine pumpBan air ejectorCa feed water pumpDa condensate pump

单选题Which of the following methods is normally used to control the temperature of air distributed from individual cooling coils in an air conditioning system using a chilled water circulation system?()AA room thermostat activates an electric heater at each individual chilled air outlet when necessaryBVarying the number of passes the air makes across the coilsCVarying the temperature of the water through the coilsDVarying the quantity of water flowing through the coils

单选题Which of the following conditions can cause below normal air pressure in the intake manifold of a turbocharged diesel engine?()AExcessive piston blow-by to the manifoldBInsufficient cooling water flowCAccumulated water in the air boxesDClogged air intake filters

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单选题请阅读 Passage 1,完成第 21~25小题。Passage 1These days,many large city buildings are equipped with their own air-conditioning systems.These systems help keep the buildings cool,but they can also damage the environment.Since they use a lot of electricity,for instance,they contribute indirectly to global warming.In addition,the water that flows through the systems is often cooled using chemicals called chlorofluorocarbons,or CFCs,that are believed to damage the Earth's ozone layer.Recently,though,a system has been built in the city of Toronto,Canada,that cools buildings with little damage to the environment. In the traditional air-conditioning systems found in most large buildings,water is pumped through the building in a continuous cycle.The water is first cooled to a temperature of 4℃ in machines called chillers.It is then sent to individual units that cool the air in each room.As the water flows through the building,it gradually becomes warmer.Finally,it reaches the roof ,where it is left to cool down naturally in a water tower.After that it is returned to the chillers,where the cycle begins again.Toronto lies on the shore of Lake Ontario,one of North America's Great Lakes,and the new system makes use of cold water taken from about 80 meters below the surface of the lake.At this depth,the water in the lake remains at 4℃ all year round.This is exactly the temperature to which the water in air-conditioning systems is cooled.However,the water from the lake is not pumped directly into the air-conditioning systems.Instead,it is used to cool the water that is already inside the air-conditioning systems.After that,the lake water is added to the city's ordinary water supply.Enwave,the company that developed this deep-lake cooling system,says that it uses 75 percent less energy than traditional air conditioning.And since no CFCs are used,no damage can be caused to the ozone layer.Not every city is located next to a large lake,but experts believe that systems like the one being used in Toronto could be built elsewhere by using other natural sources of cold water.What is one problem with traditional air-conditioning systems?AThe chemicals they use sometimes pollute the water supply.BThey often damage the buildings that they are trying to cool.CThere are not enough CFCs in the world to cool all the buildings.DThe method they use to cool water is thought to harm the ozone layer.

问答题Practice 4  The problem of pollution is also of great social concern. Continued population increase, accompanied by a rise in the level of living standards, not only threatens to exhaust American resources but pollutes the environment to such an extent that production in the thickly settled area is impossible without damaging the health of the local residents.  Smog, once an urban annoyance, is now recognized as a health risk, and the automobile has been pinpointed as the principal culprit. Heavy industries have been blamed for river, soil, air, noise and visual pollutions. DDT and other chemical remedies have been doing more ecological harm than the good that they may have brought along.  Several decades ago, Americans dumped raw sewage into rivers and many industrial plants are now still dumping chemical pollutants into lakes, rivers and oceans. Oceans used to be and are still being considered to be a reserve of seafood. Today, after the oceans have become the home of all pollutants, this use of the oceans is being reduced at an alarming rate.  The worst pollution threat is concentrated in and near large cities. There the people-made pollutants increasingly surpass the ability of air and water to dilute (冲淡;稀释) the contaminants (污染物) to safe levels. The natural ecological cycle depends on plants, which absorb some pollutants and release oxygen to the air. But near large cities, natural vegetation becomes scarce, and introduced trees, ornamental shrubs and gardens are far from adequate in absorbing motor vehicle and industrial air pollutants. Finally, some pollutants, most notably atomic waste, may continue to contaminate air, land, and water for thousands of years. Therefore, ecocrisis—ecocatastrophe or ecocide—has been for some time one of the major concerns of not only the ecoactivists and environmentalists, but of many scientists of other fields and the government authorities of many countries as well.