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. _________(46)
A.Poison makes people sick B.It is in the air that people breathe C.We can not live without water D.Water is used again and again E.only if people work with the system and not against it F.It might disappear into the air quickly正确答案B
