【正确答案】 B

【答案解析】[听力原文] 18-21
Until the twentieth century cigarettes were not an important threat to public health, since the cigarette industry began in the 1870s. However, Cigarette-manufacturing machine has developed rapidly, which made it possible to produce great number of cigarettes very quickly, and it reduced the price.
Today cigarette smoking is a widespread habit. About 43 percent of the men and 31 percent of the adult women in American smoke cigarettes regularly. It is encouraging to note, however, millions of people have given up the smoking habit.
Income, education and occupation all play in determining a person's smoking habit. City people smoke more than people living on farms. On the one hand, well-educated men with high income are less likely to smoke cigarettes than men with fewer years of schooling and lower income. On the other hand, if a well-educated man with a high income smokes at all, he is likely to smoke more packs of cigarettes per day. The situation is somewhat different for women. There are slightly more smokers among women with higher family income and higher education than among the lower educational groups. These more highly educated women tend to smoke more heavily.

根据是文中的“…cigarette-manufacturing machine has developed rapidly，which…reduced the price”。

【正确答案】 B

【答案解析】根据是“About 43 percent of the men and 31 percent of the adult women in America smoke cigarettes regularly”。

【正确答案】 A

【答案解析】根据是“Income, education and occupation all play a part in determining a person's smoking habits”。

【正确答案】 C

【答案解析】根据最后一句话“These more highly educated women tend to smoke more heavily”。