共用题干Obtaining Drinking Water from Air HumidityNot a plant to be seen,the desert ground is too dry.But the air contains water,and research scientistshave found a. __________(51)of obtaining drinking water from air humidity."The process we have developed is based exclusively on renewable energy sources_________(52)thermal solar collectors andphotovoltaic（光电的）cells , ________( 53 ) makes this method completely energy-autonomous. It will ____________( 54 ) function in regions where there is no electrical infrastructure（基础设施）,"says Siegfried Egner,head of the research team. The principle of the_________(55)is as follows:hygroscopic（吸湿的） brine（盐水）一saline（含盐的）solution which absorbs moisture一runs down a tower-shaped unit and absorbs water from the air. It is then sucked__________(56)a tank a few meters off the ground in which a vacuum prevails.Energy from solar collectors_________(57)up the brine,which is diluted by the water it has__________ (58).Because of the vacuum,the boiling point of the liquid is lower than it would be under__________(59) atmospheric pressure. The evaporated (蒸发的）, non-saline water is condensed and runs down through a completely filled tube in a controlled manner. The gravity of this water column_______(60)produces the vacuum and so a vacuum pump is not needed.The reconcentrated brine________(61)down the tower surface again to absorb moisture from the air."The concept is suitable for various water________(62).Single一person units and plantssupplying water to entire hotels are conceivable,"says Egner. Prototypes have been built for_______(63)system components一air moisture absorption and vacuum evaporation一and the research scientistshave already __________(64)their interplay on a laboratory scale.In a further ________(65)the re- searchers intend to develop a demonstration facility._________(52)A:in spite ofB:because ofC:as a result ofD:such as
共用题干
Obtaining Drinking Water from Air Humidity
Not a plant to be seen,the desert ground is too dry.But the air contains water,and research scientists
have found a. __________
(51)of obtaining drinking water from air humidity."The process we have
developed is based exclusively on renewable energy sources_________(52)thermal solar collectors and
photovoltaic（光电的）cells , ________( 53 ) makes this method completely energy-autonomous. It will
____________( 54 ) function in regions where there is no electrical infrastructure（基础设施）,"says Siegfried
Egner,head of the research team. The principle of the_________(55)is as follows:hygroscopic（吸湿的）
brine（盐水）一saline（含盐的）solution which absorbs moisture一runs down a tower-shaped unit and absorbs
water from the air. It is then sucked__________(56)a tank a few meters off the ground in which a vacuum
prevails.Energy from solar collectors_________(57)up the brine,which is diluted by the water it has
__________ (58).
Because of the vacuum,the boiling point of the liquid is lower than it would be under__________(59)
atmospheric pressure. The evaporated (蒸发的）, non-saline water is condensed and runs down through a
completely filled tube in a controlled manner. The gravity of this water column_______(60)produces the
vacuum and so a vacuum pump is not needed.The reconcentrated brine________(61)down the tower
surface again to absorb moisture from the air.
"The concept is suitable for various water________(62).Single一person units and plants
supplying water to entire hotels are conceivable,"says Egner. Prototypes have been built for_______
(63)system components一air moisture absorption and vacuum evaporation一and the research scientists
have already __________(64)their interplay on a laboratory scale.In a further ________(65)the re-
searchers intend to develop a demonstration facility.
Obtaining Drinking Water from Air Humidity
Not a plant to be seen,the desert ground is too dry.But the air contains water,and research scientists
have found a. __________
(51)of obtaining drinking water from air humidity."The process we have
developed is based exclusively on renewable energy sources_________(52)thermal solar collectors and
photovoltaic（光电的）cells , ________( 53 ) makes this method completely energy-autonomous. It will
____________( 54 ) function in regions where there is no electrical infrastructure（基础设施）,"says Siegfried
Egner,head of the research team. The principle of the_________(55)is as follows:hygroscopic（吸湿的）
brine（盐水）一saline（含盐的）solution which absorbs moisture一runs down a tower-shaped unit and absorbs
water from the air. It is then sucked__________(56)a tank a few meters off the ground in which a vacuum
prevails.Energy from solar collectors_________(57)up the brine,which is diluted by the water it has
__________ (58).
Because of the vacuum,the boiling point of the liquid is lower than it would be under__________(59)
atmospheric pressure. The evaporated (蒸发的）, non-saline water is condensed and runs down through a
completely filled tube in a controlled manner. The gravity of this water column_______(60)produces the
vacuum and so a vacuum pump is not needed.The reconcentrated brine________(61)down the tower
surface again to absorb moisture from the air.
"The concept is suitable for various water________(62).Single一person units and plants
supplying water to entire hotels are conceivable,"says Egner. Prototypes have been built for_______
(63)system components一air moisture absorption and vacuum evaporation一and the research scientists
have already __________(64)their interplay on a laboratory scale.In a further ________(65)the re-
searchers intend to develop a demonstration facility.
_________(52)
A:in spite of
B:because of
C:as a result of
D:such as
A:in spite of
B:because of
C:as a result of
D:such as
参考解析
解析：根据上下文可知“科研人员发现了一种从空气里的水分中获取饮用水的方法”，所以 选C。
such as表示“比如”，用于列举。
此处为非限制性定词从句，所以用which。
根据上文“这使得该方法在能量方面完全自主”可知，这里指“即使在没有电力基础设 施的地方仍可起到作用”，所以选D。
根据上下文可知“这套工序的原理如下”，所以选B。
suck into表示“吸入”。
根据上下文可知这里指“来自太阳能收集器的能量将盐水加热”。
absorb表示“吸收”，这里指稀释所吸收的水。
normal“正常的”，这里指“在真空环境中，液体的沸点要比在正常大气压下低。”
continuously“不间断地”;suddenly“突然地”;typically“典型地”;senously“严重地”。根据上下文可知，这里指“水柱的重力持续制造真空状态，所以不需要真空泵”。
run原意为“跑”，但这里是“流动”的意思，run down“沿着······流动”。根据上下文可知“二次浓缩的盐水会沿着塔状物再次向下流去吸收空气中的水”，所以选D。
根据上下文可知“这一理念适用于各种各样的水的使用者”，所以选A。
both"（两者）都”；因为这里是强调空气水汽吸收器和真空蒸汽机两个机器之间的作用 效果，所以选A。
这里指“科研人员已经在实验室里测试了它们相互作用的效果”，所以选C。
step“步骤”;instrument“工具”;case“案例”;ground“地面”。根据上下文可知“在下一步 的研究中，研究者会开发出一套用于展示的设备”，所以选B。
such as表示“比如”，用于列举。
此处为非限制性定词从句，所以用which。
根据上文“这使得该方法在能量方面完全自主”可知，这里指“即使在没有电力基础设 施的地方仍可起到作用”，所以选D。
根据上下文可知“这套工序的原理如下”，所以选B。
suck into表示“吸入”。
根据上下文可知这里指“来自太阳能收集器的能量将盐水加热”。
absorb表示“吸收”，这里指稀释所吸收的水。
normal“正常的”，这里指“在真空环境中，液体的沸点要比在正常大气压下低。”
continuously“不间断地”;suddenly“突然地”;typically“典型地”;senously“严重地”。根据上下文可知，这里指“水柱的重力持续制造真空状态，所以不需要真空泵”。
run原意为“跑”，但这里是“流动”的意思，run down“沿着······流动”。根据上下文可知“二次浓缩的盐水会沿着塔状物再次向下流去吸收空气中的水”，所以选D。
根据上下文可知“这一理念适用于各种各样的水的使用者”，所以选A。
both"（两者）都”；因为这里是强调空气水汽吸收器和真空蒸汽机两个机器之间的作用 效果，所以选A。
这里指“科研人员已经在实验室里测试了它们相互作用的效果”，所以选C。
step“步骤”;instrument“工具”;case“案例”;ground“地面”。根据上下文可知“在下一步 的研究中，研究者会开发出一套用于展示的设备”，所以选B。
相关考题：
BThe world is not only hungry，it is also thirsty for water． this may seem strange to you，since nearly 75% of the earth is covered with water． But about 97% of this water is sea water．Man can only drink and use the other 3% fresh water that comes from rivers，lakes，under-ground and other places． And we cannot even use all of that，because some of this fresh water has been made dirty．At the moment，this small amount(数量) of fresh water is still enough for us． However，our need for water is getting greater and greater． Only if we take steps to solve this problem now，we can get away from a serious world water shortage later on． The people of the world cannot have an enjoyable life without enough clean water．On one hand we should stop wasting this little water of ours，on the other hand we should find ways to reuse it，but this has not been done widely．Today，in most large cities，water is used only once and it then returns to the sea or runs into underground places．lf we can make it clean again，it can be used once more just as if it were fresh from a spring．But even if large cities reuse its water，we still would not have enough in the future． Where．could we turn to next for water? To the ocean! How can we do to make use of this great a-mount of sea water? We can take the salt from the water to make it fresh．So if we take all these steps，we'll be in no danger of drying up!( )26． Why does the writer say that the world is thirsty for water?A． The amount of fresh water is really very small．B． The people of the world waste too much water．C． The people of the world have to drink a lot of water every day．D． There are too many people in the world needing water．
What is head tank in the closed cooling water system used for?A.for the release of air from the cooling waterB.providing expansion room for heated cooling waterC.a place for implementing water and water treatment agentD.all of the above
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
From what you _____, you can understand why an object weighs less in water than in air.A、had learntB、will learnC、have learntD、can learn
The distance from the still water level (corrected for tides and storm surge) to the bottom of the hull of a ship is the ______.A.air gapB.freeboardC.penetrationD.water depth
Steam smoke will occur when ______.A.extremely cold air from shore passes over warmer waterB.warm dry air from shore passes over cooler waterC.cold ocean water evaporates into warm airD.cool rain passes through a warm air mass
共用题干WaterEarth is like a big blue marble.From high above the Earth and from the moon,the planet gleams and shines.The blue water in the oceans and seas of the Earth makes a dramatic image.The white clouds above the Earth add beauty to the picture.Water is the source of this beauty and the source of life on Earth.It is the reason people can live on this planet. Water is everywhere.(46)_______.It is in the soil,the ground that grows the food.Water is in rock deep under the ground, in natural holding areas一in storage.In a real sense,water keeps Earth alive.Nature has an unchanging amount of water. Nature has a perfect system for recycling water. (47)_____.It falls as rain.Then it goes to one of three places.It might sink slowly through the soil into the natural holding areas in the rock.(48)_______一by becoming vapor,or gas.It might run off into streams,rivers and oceans.By itself,nature can keep the balance and provide plenty of clean water for us.Nature recycles water.However,people cause problems for this natural recycling system.Nature's recycling system can work well(49)________.Some ways that people upset nature are easy to understand.For example, dirty sewage（污水沟系统）water from homes and factories must not mix with drinking water. People get sick from drinking contaminated water. Sometimes water from factories goes into streams and rivers.It enters into the groundwater. It can flow into lakes too.This kind of contamination from industry(waste water from factories) can be dangerous for people.If water contains poisons and chemicals,it is poison.(50)________;some poisons kill people as well as birds and animals.Without knowing,people can upset nature's recycling system.Lakes and rivers add beauty to the world. People enjoy water for entertainment purposes,too. People enjoy swimming and playing in the cool water of a lake in the summer. They like to ride on boats on rivers.Many people enjoy catching fish in the rivers.They fish for food and for sport.However,in some places,the water of the lakes and rivers is no longer safe.These rivers and lakes are contaminated.The fish are dying because of the chemicals from farms and factories.People cannot swim in the polluted water._________（49）A:Poison makes people sickB:It is in the air that people breatheC:We can not live without waterD:Water is used again and againE:only if people work with the system and not against it F: It might disappear into the air quickly
共用题干Obtaining Drinking Water from Air HumidityNot a plant to be seen,the desert ground is too dry.But the air contains water,and research scientistshave found a. __________(51)of obtaining drinking water from air humidity."The process we have developed is based exclusively on renewable energy sources_________(52)thermal solar collectors andphotovoltaic（光电的）cells , ________( 53 ) makes this method completely energy-autonomous. It will ____________( 54 ) function in regions where there is no electrical infrastructure（基础设施）,"says Siegfried Egner,head of the research team. The principle of the_________(55)is as follows:hygroscopic（吸湿的） brine（盐水）一saline（含盐的）solution which absorbs moisture一runs down a tower-shaped unit and absorbs water from the air. It is then sucked__________(56)a tank a few meters off the ground in which a vacuum prevails.Energy from solar collectors_________(57)up the brine,which is diluted by the water it has__________ (58).Because of the vacuum,the boiling point of the liquid is lower than it would be under__________(59) atmospheric pressure. The evaporated (蒸发的）, non-saline water is condensed and runs down through a completely filled tube in a controlled manner. The gravity of this water column_______(60)produces the vacuum and so a vacuum pump is not needed.The reconcentrated brine________(61)down the tower surface again to absorb moisture from the air."The concept is suitable for various water________(62).Single一person units and plantssupplying water to entire hotels are conceivable,"says Egner. Prototypes have been built for_______(63)system components一air moisture absorption and vacuum evaporation一and the research scientistshave already __________(64)their interplay on a laboratory scale.In a further ________(65)the re- searchers intend to develop a demonstration facility._________(51)A:roadB:channelC:wayD:path
共用题干Obtaining Drinking Water from Air HumidityNot a plant to be seen,the desert ground is too dry.But the air contains water,and research scientistshave found a. __________(51)of obtaining drinking water from air humidity."The process we have developed is based exclusively on renewable energy sources_________(52)thermal solar collectors andphotovoltaic（光电的）cells , ________( 53 ) makes this method completely energy-autonomous. It will ____________( 54 ) function in regions where there is no electrical infrastructure（基础设施）,"says Siegfried Egner,head of the research team. The principle of the_________(55)is as follows:hygroscopic（吸湿的） brine（盐水）一saline（含盐的）solution which absorbs moisture一runs down a tower-shaped unit and absorbs water from the air. It is then sucked__________(56)a tank a few meters off the ground in which a vacuum prevails.Energy from solar collectors_________(57)up the brine,which is diluted by the water it has__________ (58).Because of the vacuum,the boiling point of the liquid is lower than it would be under__________(59) atmospheric pressure. The evaporated (蒸发的）, non-saline water is condensed and runs down through a completely filled tube in a controlled manner. The gravity of this water column_______(60)produces the vacuum and so a vacuum pump is not needed.The reconcentrated brine________(61)down the tower surface again to absorb moisture from the air."The concept is suitable for various water________(62).Single一person units and plantssupplying water to entire hotels are conceivable,"says Egner. Prototypes have been built for_______(63)system components一air moisture absorption and vacuum evaporation一and the research scientistshave already __________(64)their interplay on a laboratory scale.In a further ________(65)the re- searchers intend to develop a demonstration facility._________(56)A:fromB:atC:aboveD:into
共用题干Obtaining Drinking Water from Air HumidityNot a plant to be seen,the desert ground is too dry.But the air contains water,and research scientistshave found a. __________(51)of obtaining drinking water from air humidity."The process we have developed is based exclusively on renewable energy sources_________(52)thermal solar collectors andphotovoltaic（光电的）cells , ________( 53 ) makes this method completely energy-autonomous. It will ____________( 54 ) function in regions where there is no electrical infrastructure（基础设施）,"says Siegfried Egner,head of the research team. The principle of the_________(55)is as follows:hygroscopic（吸湿的） brine（盐水）一saline（含盐的）solution which absorbs moisture一runs down a tower-shaped unit and absorbs water from the air. It is then sucked__________(56)a tank a few meters off the ground in which a vacuum prevails.Energy from solar collectors_________(57)up the brine,which is diluted by the water it has__________ (58).Because of the vacuum,the boiling point of the liquid is lower than it would be under__________(59) atmospheric pressure. The evaporated (蒸发的）, non-saline water is condensed and runs down through a completely filled tube in a controlled manner. The gravity of this water column_______(60)produces the vacuum and so a vacuum pump is not needed.The reconcentrated brine________(61)down the tower surface again to absorb moisture from the air."The concept is suitable for various water________(62).Single一person units and plantssupplying water to entire hotels are conceivable,"says Egner. Prototypes have been built for_______(63)system components一air moisture absorption and vacuum evaporation一and the research scientistshave already __________(64)their interplay on a laboratory scale.In a further ________(65)the re- searchers intend to develop a demonstration facility._________(65)A:instrumentB:stepC:caseD:ground
单选题Why do some people get sick after drinking the water from the river?ABecause the river is pollutedBBecause the river makes the earth more beautifulCBecause the river can only offer water to animalsDBecause there are too many animals and plants in the river
单选题What is head tank in the closed cooling water system used for?（）Afor the release of air from the cooling waterBproviding expansion room for heated cooling waterCa place for implementing water and water treatment agentDall of the above
单选题The main purpose of starting the diesel engine on air briefly is（）Ato inspect if the cylinder has the water leakageBto expel out the residual water/gas/oil from the cylinderCto check if fuel supply is normalDA and B
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 happens in the end to the water from Lake Ontario?AIt is used by the residents of Toronto.BIt is returned to a place deep in the lake.CIt is cooled down before being used again.DIt is added to the water inside air-conditioning systems.
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
问答题Practice 1 Heat loss by sweating depends on the fact that when a liquid evaporates, it absorbs an enormous quantity of heat from its surroundings. Therefore, when I am of sweat evaporate, a great deal of heat is absorbed from the surface of the body in contact with it. 1______ 2______ The first is the amount of movement of air surrounding the body. The second is the amount of water vapor in the air that surrounds the body. 3______ For this reason, sweat evaporates very rapidly on windy days, and the rate of heat loss by sweating is much more than on a still day. This accounts for the fact that hot still days are much less comfortable than hot windy days. In contrast, the sweat evaporates very rapidly on hot windy days, and cools the body quickly and effectively. 4______ When air is carrying the maximum amount of water vapor that it can hold, it is said to be 100% saturated with water vapor. The relative humidity of the air is said to be 100%. Under these conditions the air cannot carry any water, so no water can evaporate. When the relative humidity is high, therefore, sweat cannot evaporate. Instead, it forms large drops and runs off your skin without cooling you. 5______ It is obvious that under these conditions, evaporation will be much more rapid. Therefore, sweating will be much more effective as a method of losing heat from the body. On a hot dry day, sweat evaporates as soon as it is formed, and you feel reasonably cool even though the temperature of your environment is very high.[A] When the air is very dry and carries no water at all, the relative humidity is said to be 0%.[B] The second factor is the amount of water vapor in the air－the humidity.[C] Hot windy days are much more comfortable than hot still days.[D] This heat transfer occurs even if the environment is hotter than the body.[E] When air moves over the surface of water, the amount of evaporation is greatly increased.[F] You might expect the highest incidence of a heat stroke when the maximum temperature is 100 and humidity is 50%.[G] Two factors affect the rate of evaporation of sweat, and therefore the effectiveness of sweating as a method of cooling the body.
单选题The engine is started with （） supplied from air receivers.Apressure oilBpressure waterCcompressed airDcooling water
单选题Vents are led from the engine to head tank （） from the cooling water.Afor the release of airBfor the release of waterCin order to the release of airDbecause the release of air
单选题Which statement concerning the collection of fresh water is FALSE?（）AFresh water may be obtained from fishBlifeboat covers or canopies should be washed with rain before drinking water is collectedCFresh water may be collected from condensation inside the life-raftDFreshwater cannot be produced from standing seawater
单选题Which statement concerning the collection of fresh water is FALSE?（）AFresh water may be obtained from fishBLifeboat covers or canopies should be washed with rain before drinking water is collectedCFresh water may be collected from condensation inside the liferaftDSeawater should never be consumed
单选题The air spaces in the floor of an inflatable liferaft will provide protection against（）.Aasphyxiation from CO2Bloss of air in the sides of the raftCrough seasDcold water temperatures
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Steam smoke will occur when（）.AExtremely cold air from shore passes over warmer waterBWarm dry air from shore passes over cooler waterCCold ocean water evaporates into warm airDCool rain passes through a warm air mass
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.
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What is NOT a function of the air supply of a covered lifeboat?（）AProvides air for engine combustionBPressurizes water spray systemCProvides air for passenger respirationDPrevents smoke and other noxious fumes from entering craft
单选题The purpose of an air compressor unloading device is to （）Adrain water from the air receiverBdrain water from the cylindersCdelay the compression process until the motor is up to speedDcheck pump alignment