40. A. oceans　　　　　 B. seas　　　　 C. rivers　　　 D. wells

39. A. other　　　　　 B. another　　 C. \　　　　　 D. either

38. A. dirty　　　　　 B. clean　　　　 C. salty　　　 D. heavy

37. A. center　　　　　 B. weight　　　 C. number　　 D. surface

　　 The world is not only hungry, it is also thirsty for water. This may seem 　36 to you, since nearly 70% of the earth’s 　37 　is covered with water. But about 97% of this huge amount is sea water, or 38 　water. Man can only drink and use the　 39　 3%--- the fresh water from 　40 　, lakes, underground and other sources. And we cannot even use　 41 　of that, because some of it is in the

42 　of icebergs and glaciers(冰川). Even worse , some of it has been　 43 　.

　　 However, 44 　things stand today, this small amount of fresh water is

45 　enough for us. But our need for water is increasing rapidly--- almost day46　 day. Only if we take steps to 47 with this 　48 　now can we avoid a severe worldwide water shortage 49 on.

　　 We all have to learn how to stop 　50 　our valuable water. One of the first

51 　is to develop ways of reusing it.

　　 Today in most cities, water is used only 　52 and then sent out into a sewage system(下水道). From there it returns to the sea 　53 　runs into underground storage tanks(箱). But it is possible to pipe 　54 water to a purifying plant(工厂). There it can be treated with chemicals so that it can be used again, just as if it 　55 fresh from a spring(泉水).

36. A. interesting　　　 B. exciting　　　 C. surprised　 D. pleasing

35.Many people find ________ useful to learn English well.

　　　 　A.that　　　　　 B.it　　　　　　 C.this　　　　 D.to be

34.---How often do you go to the library?

　 --- _______.

　　 A.Once two days　　　　　　　　 B. Every few days

　　 C.Each third day　　 　　　　　　D. Every a few days

33.At one time, there were long queues of people　　　　　　 outside the CAAC　 offices

　　　 A.who waiting　　　　　　　　　 B.waiting

　　　　 C.were waiting　　　　　　　　 D.who are waiting

32.The map of the world still ______ where the teacher had _____ it before.

　 A. lay,laid　　 B. lay,lie　　 C. lied,lain　　　 D.laid,lied

31.We considered him　　　　　　 honest man.

　　　　 A.is an　　 　　B.was an　　 C.to be a　　　　 D.to be an