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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. By "dropout" the author means（）.
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试述房价与地价的关系？
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圆锥破碎机的（），就是利用装设在机架周围的弹簧作为保险装置。
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卷烟零售客户关注的是卷烟调拨价格和批发价格。
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塑像仪有哪些内容？
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铸坯表面缺陷主要是受钢水在（）凝固过程控制的。
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硬膜外麻醉的最严重并发症是（）。
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呼吸功能障碍者行择期手术，下列术前准备，不正确的是（）。
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患者女性，20岁．主诉阴道瘙痒，阴道分泌物增多并有难闻的气味。患者否认发热、背痛、排尿困难、血尿、或阴道出血。她与多位性伴侣有频繁性生活，很少使用防护措施。检查中有中量绿色泡沫状分泌物。对分泌物进行氨臭味试验检测为阴性，测得pH值为6。显微镜下见多鞭毛的微生物。该患者最可能的诊断是（）。
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下列哪几类剂型可以用来喷雾（）