完形填空（共20小题，每小题1分，满分20分）
从A.B.C.D四个选项中，选出可以填入空白处的最佳选项。
In the past, man did not have to think about the protection of his environment．There were few people on the earth, and natural resources seemed to be 31 ．
Today things are 32 , the world has become too 33 ．We are using up our natural resources too quickly and at the same time we are 34 our environment with dangerous chemicals．If we continue to do this, human life on the earth 35 survive．
Everyone 36 today that if too many fishes are taken from the sea, there will soon be none left． Yet, with modern fishing 37 , more and more fishes are caught．We know that if too many trees are cut down, 38 will disappear and nothing will grow on the earth．Yet we __39 to use bigger and more powerful machines to 40 more and more trees．
We realize that if rivers are polluted with waste products from factories, fish will die． 41 , in most countries wastes are 42 put into rivers or into the sea, and there are 43 laws to stop this．
We know, too, that if the 44 of the world continues to rise at the present rate , in a few years there will not be enough 45 ．What can we do to solve these problems?
If we eat more vegetables and less 46 ,there will be more food available for everyone．Land that is used to grow crops 47 five times more people than land where animals are kept．
Our natural resources will 48 longer if we learn to recyclethem．
The world population will not rise so quickly if people use modern methods of birth 49 ．
Finally, if we educate people to think about the problems, we shall have a better and cleaner 50 in the future．
1.A．beautiful B．unlimited C．unusual D．valuable
2.A．common B．the same C．changeable D．different
3.A．crowded B．small C．dirty D．busy
4.A．protecting B．saving C．polluting D．fighting
5.A．may not B．will not C．shall not D．could not
6.A．wonders B．realizes C．considers D．discovers
7.A．poles B．boats C．methods D．ideas
8.A．mountains B．the sea C．trees D．forests
9.A．continue B．have C．ought D．go on
10.A．grow B．plant C．save D．cut down
11.A．Thus B．However C．Generally D．Therefore
12.A．still B．even C．also D．certainly
13.A．many B．none C．some D．few
14.A．production B．pollution C．population D．development
15.A．houses B．vegetables C．food D．places
16.A．fruit B．meat C．fish D．grain
17.A．feeds B．increases C．supplies D．helps
18.A．use B．stay C．keep D．last
19.A．control B．born C．plan D．pay
20.A．nature B．sea C．planet D．forest
---My name is Annabelle. Shall I spell it for you?
---___.
A. If you don’t mind B. Not at all
C. Take it easy D. Nice to meet you
Wind power is a source of energy we may return in the near future.
A. on which B. by which C. to which D. from which
The committee is discussing the problem right now. It will _____ have been solved by the end of next week.
A. generally B. hopefully C. immediately D. likely
When you learn a foreign language, ________you must forget your own one.
A. above all B. after all C. in all D. at all
Mark ______ a basketball game in the stadium that _______ 5000 people.
A. holds; is holding B. is holding; holds
C. holds; holds D. is holding; is holding
