完形填空（共20小题，每小题1分，满分20分）从A.B.C.

科目：英语
题型：完型填空
难度：中等
人气：2097

题文

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．