Directions: For each blank in the following passage there are words or expressions marked A, B, C and D. Fill in each blank with the word or phrase that best fits the context.
In the past, man did not have to think about the protection of the environment. There were few people on the earth, and natural resources seemed to be 36 ___________ .
Today things are different, the world has become too 37________. We’re using up our natural resources too quickly, and at the same time we are 38__________our environment with dangerous chemicals. If we continue to do this, human life on the earth will not survive.
Everyone realizes today that if too many fish are taken from the sea, there will soon be none left. Yet, with modern fishingmethods, more and more fish are caught. We know that if too many 39_____ are cut down, forests will disappear and nothing will grow on the land. Yet, we 40______ to use bigger and more powerful machines to 41_________more and more trees.
We realize that if rivers are polluted with waste products from factories, we will die. 42_____, in most countries wastes are still 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 enoughfood. 45________ can we deal with these problems ?
If we eat more vegetables and lessmeat, there will be more food available for everyone. Land that is used to grow cropson feeds five times more people than land 46_____ animals are kept. Our natural resources will last longer if we learn to recycle them. The world population will not rise so quickly if people use modern methods of birth control. Finally, if we educate people to think about the problems, we 47_____ have a better and clearer planet in the future.

A．beautiful B．unlimited C．rare D．valuable

A．crowded B．small C．dirty D．busy

A．protecting B．saving C．polluting D．fighting

A．mountains B．flowers C．trees D．grass

A．continue B．have C．ought D．go on

A．grow B．plant C．save D．cut down

A．Thus B．However C．Generally speaking D．Therefore

A．too many B．a few C．some D．few

A．production B．pollution C．population D．revolution

A．What B．How C．Why D．Where

A．that B．which D．what

A．may B．can C．should D．shall