骨软骨瘤多见于（） A.长骨骨端 B.长骨骨骺 C.长骨骨干 D.长骨干骺端 E.扁

集中式供水的卫生调查内容包括（）。

A.水源卫生调查、水厂调查、出厂水质监测

B.水源卫生调查、管网末梢水调查和水质监测

C.水厂调查、管网末梢水调查和末梢水监测

D.水源调查、水厂调查和水源水监测

E.水源卫生调查、水厂调查和水质监测

She       volleyball regularly for many years when she was young.

A．was playing

B．played

C．has played

D．had played

一个正方体的棱长是8米，它的表面积是[ ]

A．（8×6）平方米 

B．（8×8×6）平方米

C．（8×8×4）平方米

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（）.

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

实施股票分割与发放股票股利产生的效果相似，它们都会（）。

A.改变股东权益结构

B.增加股东权益总额

C.降低股票每股价格

D.降低股票每股面值