由某地300名8岁正常男孩收缩压估计该地8岁正常男孩平均收缩压的95%可信区间，可选

运营线上涵洞应能通过规定频率（）一遇洪水及历史上最大洪水。

A、10年

B、30年

C、50年

D、100年

捣固焦炉的入炉煤饼是没有锥度的。

（）及其预告信号机采用方形背板，并在机柱上涂有黑白相间的斜线，以区别于一般信号机。

A、遮断

B、容许

C、接近

D、通过

我国社会主义初级阶段实行以公有制为主体、多种所有制经济共同发展的基本经济制度，促进了生产力的发展。实行这种制度是遵循了

A．生产力决定生产关系的原理

B．经济基础决定上层建筑的原理

C．社会经济制度决定生产力状况的原理

D．生产力内部矛盾运动的原理

Water is (41) important of all the things we (42) and drink. Not many people understand this, (43) it’s quite true. The human body (人体) can go (44) food for a long time, but two (45) three days without water can usually (46) people die.
Many people don’ t understand how much water the human body needs to work well and many people do not drink (47) , even (48) hot weather.
Our body is (49) water, about 65% to 75%, ff we do not have enough water, we’ll (50) tired and many will get ill. So you see, how important water is to us all.

[A] very [B] more [C] the most