四
　　Today ,as in every other day of the year ,more than 3000 U.S. adlescents will smoke their first cigarette on their way to becoming regular smokers as adults. During their lifetime,it can be expected that of these 3000 about 23 will be murdered,30 will die in traffic accidents, and nearly 750 will be killed by a smoking-related disease. The number of deaths attributed to cigarette smoking outweithts all other factors, whether voluntary or involuntary, as a cause of death.

　　Since the late 1970s, when daily smoking among high school seniors reached 30 precent , smoking rates among youth have declined . While the decline is impressive ,several important issues must be raised.

　　First, in the past several years,smoking rates among youth have declined very little. Second,in the late 1970s ,smoking among male high school seniors exceeded that among female by nearly 10 percent . The statistic is reversing.Third ,several recent studies have indicate high school dropouts have excessively high smoking rates, as much as 75 percent .

　　Finally, thouth significant declines in adolescent smoking have occurred in the past decade,no definite reasons for the decline exist. Within this context,the Naional Cancer Instiute (NCI) began its current effort to determine the most effecive measures to reduce smoking levesl among youth.
　　1.According to the author, the deaths among youth are mainly caused by _____.
　　a.traffic accidents
　　b.smoking-related desease
　　c.murder
　　d.all of these

　　2.Every day there are over_____high school strdents who will become regular smoker.
　　a.75
　　b.23
　　c.30
　　d.3000

　　3.By "dropout" the author means______.
　　a.students who failed the examination
　　b.students who left school
　　c.students who lost their way
　　d.students who were driven out of school

　　4.The reason for declining adolescent smoking is that ________.
　　a.NCI has taken effective measures
　　b.smoking is prevented among high school seniors
　　c.there are many smokers who have died of cancer
　　d.none of these

　　5.What is implied but not stated by the author is that ________.
　　a.smoking rates among youth have declined very little
　　b.there are now more female than male smokers among high school seniors
　　c.high smoking rates are due to the incease in wealth
　　d.smoking at high school are from low socio-economic backgrounds
　　答案：bdbdb