few people on the earth, and natural resources seemed to be __1__.

　　Today things are __2__： the world has become too __3__. We are using up our natural resources too quickly, and at the same time we are __4__ our environment with dangerous chemicals. If we continue to do this, humans on the earth will not __5__.

　　Everyone __6__ today that if too many fish are taken from the sea, there will soon be none left. However, with modern fishing __7__， more and more fish are caught. We know that if too many trees are cut down, __8__ will disappear. Yet, we __9__ to use bigger and more powerful machines to __10__ more and more trees.

　　We realize that if rivers are polluted with waste products from factories, we will die. __11__， in most countries wastes are __12__ put into rivers or into the sea, and there are __13__ laws to stop this. We know, too, that if the __14__ of the world continues to rise at the present rate, in a few years there will not be enough food. What can we do to __15__ these problems?

　　If we eat more vegetables and less __16__， there will be more food available for everyone. Land that is used to grow crops __17__ five times more people than land where animals are kept. Our natural resources will __18__ longer if we learn to recycle them. The world population will not rise so quickly if people use modern methods of birth __19__.

　　Finally, if we educate people to think about the problems, we shall have a better and cleaner __20__ in the future.

　　语篇解读：本文是说明文。文章主要讲述在社会取得进步、物质文明高度发达的今天，环境遭到了巨大破坏，因此我们应该采取措施增强环保意识。

　　1．A.beautiful　　　　　　 B．unlimited

　　C．rare D．valuable

　　解析：选B　在过去人少的时候，自然资源似乎是无穷尽的(unlimited)。

　　C．changeable D．different

　　解析：选D　与上一段形成对比，今天形势发生了变化，与以前不同(different)了。

　　3．A.crowded B．small

　　C．dirty D．busy

　　解析：选A　今天的世界由于人口增长而变得很拥挤。crowded表示人多而"拥挤"与上文中的"few people"形成对比。

　　4．A.protecting B．saving

　　C．polluting D．fighting

解析：选C　根据实际情况，以及下文的叙述，人们在急剧消耗自然资源的同时也在