问题
选择题
如果水果店里运苹果m千克，比梨的3倍多x千克，梨的千克数可表示为[ ]
A. m÷3-x
B.（m-x）÷3
C.（m+x）÷3
答案
答案：B
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如果水果店里运苹果m千克，比梨的3倍多x千克，梨的千克数可表示为[ ]
A. m÷3-x
B.（m-x）÷3
C.（m+x）÷3
答案：B
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____36____ . Today things are___37_____, the world has become too___38____ . We are using up our natural resources too quickly, and at the same time we are___39____ our environment with dangerous chemicals. If we continue to do this, human life on the earth ___40____survive. Everyone___41_____ today that if too many fish are taken from the sea, there will soon be none left. Yet, with modern fishing__42_____ , more and more fish are caught. We know that if too many trees are cut down, ___43____will disappear and nothing will grow on the land. Yet, we ___44_____to use bigger and more powerful machines to __45____more and more trees. We realize that if rivers are polluted with waste products from factories, we will die.___46_____, in most countries wastes are ___47______put into rivers or into the sea, and there are _48_____laws to stop this. We know, too, that if the___49____ of the world continues to rise at the present rate, in a few years, there will not be enough___50_____. What can we do to solve these problems ? It we eat more vegetables and less___51____, there will be more food available for everyone. Land that is used to grow crops __52_____five times more people than land where animals are kept. Our natural resources will _53_____longer if we learn to recycle them. The world population will not rise so quickly if people use modern methods of birth__54_______ . Finally, if we educate people to think about the problems, we shall have a better and clearer ___55____in the future.
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水中山的倒影 
屏幕上的手影
瓶子在平面镜中的像