15.A.at least　　　 B.less than　　　 C.more than　　 D.at most

4

Today more and more people live in cities.So there is usually__1__in a city to grow food. Most of the land in a city is used__2__homes,shops,roads and parks.Most food for city people is grown in the country.It is often brought to the city by__3__,train and plane.Some food__4__comes into the city by car.

Do you live in a city?If you_5__,think of all kinds of food you eat in a day.All of the food comes from the country.The wheat for your bread is grown on farms in the country.So are vegetables.

Water is__6__thing that cities get from the country.Everyone needs water every day.We use a little of it for__7__.But we use even more to__8_bathtubs(淋浴),run showers(浴缸) and wash streets.

The water used by cities comes mostly from rain.But people__9__not use the rain that falls on cities.The rain__10__dirty as it falls__11__dirty air.Once it hits city buildings or streets,the rain will__12__more dirt.It is not good for drinking__13__bathing.

So cities must reach out to the clean country for water.There,the rain falls through__14__onto trees and grass.The fallen rain runs__15__rivers and lakes.So it is important to keep both cities and country clean.

14.A.Early　　　 B.Late　　　　 C.Later　　　　 D.Earlier

13.A.give away　 B.fly away　　　 C.get away　　　 D.blow away

12.A.take　　　　 B.bring　　　　 C.carry　　　　 D.get

11.A.strong　　　 B.more strong　 C.the strongest　 D.strongly

10. A.hit　　　　 B.arrive　　　　 C.happen　　　 D.reach

9. A.must be taken 　　　　　　　　B.should be taken　

　 C.had to be taken　　 　　　　　　D.would be taken

8. A.make　　　　 B.have　 　　　　C.let　　　　 D.told

7. A.study　　　　 B.studying　　　 C.to study　　 D.studies

6. A.didn’t　　　　 B.still　　　　 C.ever　　　　 D.even