解析：由第二段最后一句中的"from 37 % to 30 % among 12th graders"可知12年级的学生吸烟的比例降低了7个百分点。

2. The drop in teen smoking has a lot of causes EXCEPT 　　　.

A. educating kids about smoking risks

B. efforts from health experts and organizations

C. the higher price of cigarettes

D. the cut down of the number of cigarettes

答案：D

解析：由第三、四、五段可知A、B、C三项均是青少年吸烟比例下降的原因。文中没有说香烟的数量减少了, 故D项不是原因。

3. The underlined expression"get hooked on" probably means "　　　".

A. become interested in B. get tired of

C. give up D. take no interest in

答案：A

解析：本句的意思:健康专家尤其注意青少年吸烟的问题, 因为终生的吸烟者往往在早期对吸烟着迷。get hooked on的意思为"对......着迷", 故A项为正确答案。

4. It can be inferred from the last two paragraphs that 　　　.

A. the rate of teen smoking is far lower than it was

B. cigarette smoking can be stopped sooner or later

C. there are different ideas about the drop in teenage smoking

D. no younger teens really understand the dangers of smoking

答案：C

解析：由倒数第二段第一句"But some say that the new figures aren't exactly the cause for celebration"可以推断出在青少年吸烟比例下降这个问题上, 人们有着不同的意见。A、D表述错误;B项无法从文中推出。

(二)再读文章, 完成下列练习。

根据上下文猜测画线单词或词组的含义。

5. A lot of individuals (个人) and organizations have been trying to bring down the high rates of teen smoking. 　　　　　

答案：使......降低