单选题（）is formed when the droplets or ice crystals in clouds have become sufficiently large to fall to the ground.AHumidityBTemperatureCPrecipitationDWind
单选题
（）is formed when the droplets or ice crystals in clouds have become sufficiently large to fall to the ground.
A
Humidity
B
Temperature
C
Precipitation
D
Wind
参考解析
解析：
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相关考题：
_____, water turns into ice.A、When freezingB、When frozenC、When it has been frozenD、When freezes to it
When winter comes, there are large pieces of____ ice on the surface of the river. A、capitalB、accentC、mathD、floating
The first indications a mariner will have of the approach of a warm front will be ______.A.large cumulonimbus (thunderclouds) building upB.high cirrus clouds gradually changing to cirrostratus and then to altostratusC.fog caused by the warm air passing over the cooler waterD.low dark clouds accompanied by intermittent rain
______ is the most common cause of ice formation．A.The freezing of raindrops on contact with the vessel's structureB.Drastic fall in ambient temperatureC.The deposit of water droplets on the vessel's structureD.Snowfall
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请阅读短文，完成此题。When we analyze the salt salinity(盐溶度 ) of ocean waters, we find that it varies only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction of water from the ocean by means of evaporation. In this manner, the salinity is increased, since the salt stays behind. If this is carried to the extreme, of course, white salt would be left behind; this, by the way, is how much of the table salt we use is actually obtained.The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas ofhigh rainfall or in coastal regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by-evaporation, or decreased by the addition of fresh water by precipitation.Normally, in hot regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute the sea, salinity is somewhat lower than in other oceanic areas.A third process by which salinity may be altered is associated with the formation and melting of sea ice. When seawater is frozen, the dissolved materials are left behind. In this manner, seawater directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of the surrounding water.In the Weddell Sea, the densest water in the ocean is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portion of the oceans of the world.Which of the following is not the cause of the decrease in the oceanic salinity?查看材料A．Precipitation.B．Rain and snow.C．Formation of ice.D．Addition of water by rivers.
共用题干1. Icebergs are among nature's most spectacular（壮观的）creations , and yet most people have never seen one.A vague air of mystery envelops them.They come into being somewhere in faraway, frigid waters,amid thunderous noise and splashing turbulence,which in most case no one hears or sees. They exist only a short time and then slowly waste away（消融）just as unnoticed.2. Objects of sheerest（最纯粹的）beauty they have been called. Appearing in an endless vaniety of shapes,they may be dazzlingly white,or they may be glassy blue,green or purple,tinted faintly on in darker hues.They are graceful, stately,inspiring in calm,sunlight seas.3.But they are also called frightening and dangerous,and that they are一in the night,in the fog,and in storms.Even in clear weather one is wise to stay a safe distance away from them.Most of their bulk is hidden below the water,so their underwater parts may extend out far beyond the visible top.Also,they may roll over unexpectedly,churning the waters around them.4.Icebergs are parts of glaciers that break off,drift into the water,float about awhile,and finally melt.Icebergs afloat today are made of snowflakes that have fallen over long ages of time.They embody snows that drifted down hundreds,or many thousands,or in some cases maybe a million years ago.The snows fell in polar region and on cold mountains,where they melted only a little or not at all,and so collected to great depths over the years and centuries.As each year's snow accumulation lay on the surface,evaporation and melting caused the snowflakes slowly to lose their feathery points and become tiny grains of ice.When new snow fell on top of the old,it too turned to icy grains.So blankets of snow and ice grains mounted layer upon layer and were of such great thickness that the weight of the upper layers compressed the lower ones.With time and pressure from above, the many small ice grains joined and changed to larger crystals,and eventually the deeper crystals merged into a solid mass of ice.Even in clear weather one is wise to_________.A:larger than the part above the waterB:stay near the icebergC:melt away just as unnoticedD:larger crystalsE:stay away from icebergF:above the water
共用题干1. Icebergs are among nature's most spectacular（壮观的）creations , and yet most people have never seen one.A vague air of mystery envelops them.They come into being somewhere in faraway, frigid waters,amid thunderous noise and splashing turbulence,which in most case no one hears or sees. They exist only a short time and then slowly waste away（消融）just as unnoticed.2. Objects of sheerest（最纯粹的）beauty they have been called. Appearing in an endless vaniety of shapes,they may be dazzlingly white,or they may be glassy blue,green or purple,tinted faintly on in darker hues.They are graceful, stately,inspiring in calm,sunlight seas.3.But they are also called frightening and dangerous,and that they are一in the night,in the fog,and in storms.Even in clear weather one is wise to stay a safe distance away from them.Most of their bulk is hidden below the water,so their underwater parts may extend out far beyond the visible top.Also,they may roll over unexpectedly,churning the waters around them.4.Icebergs are parts of glaciers that break off,drift into the water,float about awhile,and finally melt.Icebergs afloat today are made of snowflakes that have fallen over long ages of time.They embody snows that drifted down hundreds,or many thousands,or in some cases maybe a million years ago.The snows fell in polar region and on cold mountains,where they melted only a little or not at all,and so collected to great depths over the years and centuries.As each year's snow accumulation lay on the surface,evaporation and melting caused the snowflakes slowly to lose their feathery points and become tiny grains of ice.When new snow fell on top of the old,it too turned to icy grains.So blankets of snow and ice grains mounted layer upon layer and were of such great thickness that the weight of the upper layers compressed the lower ones.With time and pressure from above, the many small ice grains joined and changed to larger crystals,and eventually the deeper crystals merged into a solid mass of ice.With time and pressure from above,the many small ice grains joined and changed to__________, and eventually the deeper crystals merged into a solid mass of ice.A:larger than the part above the waterB:stay near the icebergC:melt away just as unnoticedD:larger crystalsE:stay away from icebergF:above the water
When the glaciers（ ）after the last ice age,the five Great Lakes of North America were formed.A.advancedB.evaporatedC.thawedD.exploded
When a governing body is formed,____qualifications for guides will be sure to follow.A.averageB.standardizedC.typicalD.indoor
共用题干Rainmaking1 The idea of rainmaking is almost as old as man,but it was not until 1946 that man succeeded in making rain.In ancient times,rainmakers had claimed to bring rain by many methods:dancing.singing-Kiiiing animals t including humans).2 For a long time,men have understood where rain comes from.Water from the surface of oceans and lakes becomes part of the air,where it forms clouds from which rain falls.But exactly what starts the formation of raindrops was not known until quite recently.A man named John Aitken proved that drops of water gather around tiny bits of dust or other matter.The centers of the drops are so small that the human eye cannot see them.Without such centers,it seems raindrops do not form.3 During World War Ⅱ,Dr.Irving Langmir,and his assistant Schaefer,were hired by the General Electric Company to study how and why ice forms on the wings of airplanes.They went to a mountain in New Hampshire,where snowstorms are common and cold winds blow.They were surprised to find that often the temperature of the clouds surrounding them was far below the freezing point,and yet ice did not form in the clouds.4 After the War,Schaefer experimented with a machine that created cold,moist air similar to the air found in clouds.To imitate the moist air of a cloud,Schaefer would breathe into the machine.Then he would drop into the freezer a bit of powder,sugar,or some other substance.For weeks and months he tried everything he could imagine.Nothing happened.No crystals of ice were formed.None of the substances would serve as the center of a snow crystal or raindrops.5 One July morning,Schaefer was dropping in bits of various substances and watching the unsuccessful results.Finally,a friend suggested that they go to eat lunch and Schaefer went with him.As usual,he left the cover of the freezer up,since cold air sinks and would not escape from the box.6 Returning from lunch,Schaefer found that the temperature of the freezer had risen to a point higher than that required for ice crystals to remain solid.There were two choices now.He could close the cover and wait for the freezer itself to lower the air temperature,or he could make the process occur faster by adding dry ice-a gas in solid form that is very,very cold.He chose the latter plan.As he dropped the steaming white dry ice into the freezer,he happened to breathe out a large amount of air.And there,before his eyes,it happened!He had made ice crystals,not by adding centers to the moisture,but by cooling the breath so much that the liquid had to form crystals!Then he began to blow his breath into the freezer and drop large pieces of dry ice through it to create crystals which became a tiny snowstorm falling slowly to the floor of his laboratory.7 After planning carefully,Schaefer made an experiment by dropping dry ice from his plane to the clouds below him.As was expected,snow formed and fell from the bottom of the cloud.Schaefer succeeded.He made history.Paragraph 2______A:Langmir and Schaefer's Work for the GE CompanyB:Langmir and Schaefer's Discovery of Rain-formingC:Men's Knowledge of Rain-formingD:Schaefer's Several Unsuccessful ExperimentsE:Schaefer's Discovery by AccidentF:Langmir and Schaefer's Successful Cooneration
共用题干Rainmaking1 The idea of rainmaking is almost as old as man,but it was not until 1946 that man succeeded in making rain.In ancient times,rainmakers had claimed to bring rain by many methods:dancing,singing,killing animals(including humans).2 For a long time,men have understood where rain comes from.Water from the surface of oceans and lakes becomes part of the air,where it forms clouds from which rain falls.But exactly what starts the forma- tion of raindrops was not known until quite recently.A man named John Aitken proved that drops of water gather around tiny bits of dust or other matter. The centers of the drops are so small that the human eye can- not see them.Without such centers,it seems raindrops do not form.3 During World War Ⅱ,Dr. Irving Langmir,and his assistant Schaefer,were hired by the General Electric Company to study how and why ice forms on the wings of airplanes.They went to a mountain in New Hampshire,where snowstorms are common and cold winds blow. They were surprised to find that often the temperature of the clouds surrounding them was far below the freezing point,and yet ice did not form in the clouds.4 After the War,Schaefer experimented with a machine that created cold,moist air similar to the air found in clouds.To imitate the moist air of a cloud.Schaefer would breathe into the machine.Then he would drop into the freezer a bit of powder,sugar,or some other substance.For weeks and months he tried everything he could imagine.Nothing happened.No crystals of ice were formed.None of the substances would serve as the center of a snow crystal or raindrops.5 One July morning,Schaefer was dropping in bits of various substances and watching the unsuccessful results.Finally,a friend suggested that they go to eat lunch and Schaefer went with him.As usual,he left the cover of the freezer up,since cold air sinks and would not escape from the box.6 Returning from lunch,Schaefer found that the temperature of the freezer had risen to a point higher than that required for ice crystals to remain solid.There were two choices now.He could close the cover and wait for the freezer itself to lower the air temperature,or he could make the process occur faster by adding dry ice a gas in solid form that is very,very cold.He chose the latter plan.As he dropped the steaming white dry ice into the freezer,he happened to breathe out a large amount of air. And there,before his eyes,it happened ! He had made ice crystals,not by adding centers to the moisture,but by cooling the breath so much that the liquid had to form crystals!Then he began to blow his breath into the freezer and drop large pieces of dry ice through it to create crystals which became a tiny snowstorm falling slowly to the floor of his laboratory.7 After planning carefully,Schaefer made an experiment by dropping dry ice from his plane to the clouds below him.As was expected,snow formed and fell from the bottom of the cloud.Schaefer succeeded. He made history.Paragraph 6__________A:Langmir and Schaefer's Work for the GE CompanyB:Langmir and Schaefer's Discovery of Rain-formingC:Men'S Knowledge of Rain-formingD:Schaefer'S Several Unsuccessful Experiments E:Schaefer's Discovery by AccidentF: Langmir and Schaefer'S Successful Cooperation
共用题干Rainmaking1 The idea of rainmaking is almost as old as man,but it was not until 1946 that man succeeded in making rain.In ancient times,rainmakers had claimed to bring rain by many methods:dancing.singing-Kiiiing animals t including humans).2 For a long time,men have understood where rain comes from.Water from the surface of oceans and lakes becomes part of the air,where it forms clouds from which rain falls.But exactly what starts the formation of raindrops was not known until quite recently.A man named John Aitken proved that drops of water gather around tiny bits of dust or other matter.The centers of the drops are so small that the human eye cannot see them.Without such centers,it seems raindrops do not form.3 During World War Ⅱ,Dr.Irving Langmir,and his assistant Schaefer,were hired by the General Electric Company to study how and why ice forms on the wings of airplanes.They went to a mountain in New Hampshire,where snowstorms are common and cold winds blow.They were surprised to find that often the temperature of the clouds surrounding them was far below the freezing point,and yet ice did not form in the clouds.4 After the War,Schaefer experimented with a machine that created cold,moist air similar to the air found in clouds.To imitate the moist air of a cloud,Schaefer would breathe into the machine.Then he would drop into the freezer a bit of powder,sugar,or some other substance.For weeks and months he tried everything he could imagine.Nothing happened.No crystals of ice were formed.None of the substances would serve as the center of a snow crystal or raindrops.5 One July morning,Schaefer was dropping in bits of various substances and watching the unsuccessful results.Finally,a friend suggested that they go to eat lunch and Schaefer went with him.As usual,he left the cover of the freezer up,since cold air sinks and would not escape from the box.6 Returning from lunch,Schaefer found that the temperature of the freezer had risen to a point higher than that required for ice crystals to remain solid.There were two choices now.He could close the cover and wait for the freezer itself to lower the air temperature,or he could make the process occur faster by adding dry ice-a gas in solid form that is very,very cold.He chose the latter plan.As he dropped the steaming white dry ice into the freezer,he happened to breathe out a large amount of air.And there,before his eyes,it happened!He had made ice crystals,not by adding centers to the moisture,but by cooling the breath so much that the liquid had to form crystals!Then he began to blow his breath into the freezer and drop large pieces of dry ice through it to create crystals which became a tiny snowstorm falling slowly to the floor of his laboratory.7 After planning carefully,Schaefer made an experiment by dropping dry ice from his plane to the clouds below him.As was expected,snow formed and fell from the bottom of the cloud.Schaefer succeeded.He made history.Schaefer found a way of how to make ice crystals______.A:imaginativelyB:recentlyC:carefullyD:unscientifically E:accidentally F:satisfactorily
单选题The proximity of pack ice may be indicated by（）.Achanges in seawater salinityBglare on clouds on the horizonCchanges in air temperatureDicebergs
单选题The joint formed when two steel plates are placed end-to-end is called a（）.AbevelBseamCbuttDbond
单选题The bore of each cylinder is formed in a liner which can be （） when worn out.AweldedBreplacedCdrilled againDbored
单选题According to the passage, which of the following is true of the ratios of oxygen isotopes in ocean sediments?AThey indicate that sediments found during an ice age contain more calcium carbonate than sediments formed at other times.BThey are less reliable than the evidence from rocks on land in determining the volume of land ice.CThey can be used to deduce the relative volume of land ice that was present when the sediment was laid down.DThey are more unpredictable during an ice age than in other climatic conditions.EThey can be used to determine atmospheric conditions at various times in the past.
单选题Cumulonimbus clouds are formed by（）.Avertical air movementsBheavy rainstormsChorizontal air movementsDany movement of moist air
单选题（）is formed when the droplets or ice crystals in clouds have become sufficiently large to fall to the ground.AHumidityBTemperatureCPrecipitationDWind
单选题When she saw the clouds, she went back to the house to _____ her umbrella.AbringBfetchCtakeDcarry
单选题Cumulus clouds that have undergone vertical development and have become cumulonimbus in form，indicate（）.Aclearing weatherBthat a warm front has passedCprobable thunderstorm activityDan approaching hurricane or typhoon
单选题The first indications a mariner will have of the approach of a warm front will be （）.Alarge cumulonimbus (thunderclouds) building upBhigh cirrus clouds gradually changing to cirrostratus and then to altostratusCfog caused by the warm air passing over the cooler waterDlow dark clouds accompanied by intermittent rain
单选题Fuel droplets injected into a diesel engine cylinder must have adequate penetration to （）Aprolong the ignition delay periodBensure the beginning of fuel injectionCthoroughly utilize the air chargeDallow controlled fuel combustion
问答题Scientists have long assumed that most of the ice that melted was in the Northern hemisphere（半球） during the 30,000-year long ice age.