练习:
1. Why does the risk of developing skin cancers in children become greater and greater?
A Because they pay little attention to their skin health.
B Because they are short of physical training.
C Because the earth’s protective ozone layer declines year after year.
D Because the earth is getting warmer and warmer.
2. How many people die from skin cancers including melanoma all over the world every year?
A An average of 66，000.
B Approximately 130，000.
C About 196，000.
D Between 2，000，000 to 3，000，000.
3. What people are more likely to develop eye cataracts?
A Fairer-skinned people.
B Darker-skinned people.
C People living near the equator.
D People living near the poles.
4. All of the following articles may use some chemicals unfavorable for the preservation of the ozone layer EXCEPT______.
A aerosols
B refrigerators
C pesticides
D medicines
5. The phrase “for good” in the last paragraph can be best replaced by______.
A permanently
B correctly
C largely
D well
答案与题解：
1.C 文章第一句就说到，由于地球起保护作用的臭氧层一直缩小，因此儿童发生皮肤癌的危险性增大，故C项应是最佳答案。
2.A 第三段第一句说，WHO在2002年的世界健康状况报告中提到，全世界每年平均有S6， 000人死于黑素瘤及其他类型的皮肤癌，故A项是正确答案。
3.C 第四段最后一句说到，住在赤道附近的人更容易患白内障，并没有提到南极、北极。至于肤色，该句说到，白人、黑人患白内障的可能性是相等的。
4.D 第五段最后一句举例说明某些杀虫剂、电冰箱及烟雾剂可能使用一些对臭氧层有害的化学物质，并没有提到供内服的药品，而且根据推理，也应将其排除在外。
5.A 短语for good或for good and all的意思是“永久地”、“决定性地”；英英词典的释义为“permanently”、“finally”、“forever”，故其他选项均不确切。