Question

13．The earth is 4，600 million years old．We humans have lived on the earth for only 35，000 years，but during this period we have changed our planet a lot in many ways．Some things we're done are evey good for the earth while some are bad．
    Fewer trees   All over the world，people have cut down millions of trees．When it rains or when the wind blows，the earth is taken away．Forests have become deserts，so more and more sorts of animals and plants are disappearing．
    Traffic and factory pollution    In big cities，cars and buses have polluted the air．Now many people in cities have health proplems．Factories have also polluted the land and the water．As a result，many rivers and lakes are now dead．
    The ozone layer （臭氧层）    Around the earth，there's a special kind of oxygen（O₂）called"oaone"（O₃）．It is important to the earth．But now air pollution is destroying it and that has made a very big hole in the ozone layer．Too much harmful radiation（辐射）from the sun passes though the hole and reaches the earth directly．This is very dangerous because it can cause cancer．
     More carbon dioxide （CO₂） Carbon dioxide in the air has increased a lot．It mainly comes from burning oil，coal and wood．This has formed a"blanket"around the each．The heat from the sun can't eacape so the temperature is rising．This is called"the greenhouse effect（温室效应）"．It causes the level of the ocean to rise and the climate（气候）of the earth to change．
    All these problems are very serious，so we must do something now．
73．Which of the following is right according to the passage？C
A．Cars don't pollute the air．
B．People cut down fewer trees．
C．Factories can pollute the water．
D．We humans have changed our planet a little．
74．What does the underlined word"it"in the passage refer to？B
A．CO₂．
B．O₃．
C．O₂．
D．H₂O．
75．What makes the level of the occeans rise？C
A．Pollution．
B．Fewer trees．
C．The greenhouse．
D．Changes in the climate．
76．What is the best title for this passage？A
A．Environment Problems．
B．Hope for the Future．
C．Pollution on the Earth．
D．The Greenhouse Effect．

Answer 1

分析 短文介绍了对地球造成破坏的两在问题：臭氧层被破坏和温室效应，提倡大家保护地球．

解答 答案：73．C  细节判断题．根据第三段句子Factories have also polluted the land and the water．工厂也污染了土地和水．可知工厂可以污染水是正确的．故选C．
74．B  细节推理题．根据上文The ozone layer （臭氧层） Around the earth，there's a special kind of oxygen（O₂）called"oaone"（O₂）．It is important to the earth．But now air pollution is destroying it．围绕地球的臭氧层，有一种特殊的氧气（O2）称为"臭氧"（O₃），对地球是很重要的．但现在空气污染正在破坏它．可知这里it指的是上文提到的臭氧，故选B．
75．C  细节理解题．根据倒数第二段最后一句This is called"the greenhouse effect（温室效应）"．It causes the level of the ocean to rise and the climate（气候）of the earth to change．这就是所谓的"温室效应"．导致海洋的水平上升和地球气候的改变．可知是温室效应．故选C．
76．A  主旨归纳题．根据整篇文章内容及其第四段句子The ozone layer （臭氧层） Around the earth，there's a special kind of oxygen（O₂）called"oaone"（O₃）．It is important to the earth．But now air pollution is destroying it．围绕地球的臭氧层，有一种特殊的氧气（O2）称为"臭氧"（O₃），对地球是很重要的．但现在空气污染正在破坏它．和 倒数第二段最后一句This is called"the greenhouse effect（温室效应）"．It causes the level of the ocean to rise and the climate（气候）of the earth to change．这就是所谓的"温室效应"．导致海洋的水平上升和地球气候的改变．可知本篇短文介绍了对地球造成破环境坏的两个问题：臭氧层被破坏和温室效应，提倡大家保护地球．故选A．

点评 在通读全文的基础上，根据全文大意，展开逻辑思维，瞻前顾后，认真观察选项，仔细推敲，确定最佳答案．