Brian is such an excellent scientist tha_爱下问搜题

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问题选择题

Brian is such an excellent scientist that we shouldn’t be surprised if he________the Noble Prize one day.[ ]

A．is awarded

B．had been awarded

C．have been awarded

D．would have been awarded

答案

答案：A

单项选择题

肺气肿由于病变导致肺毛细血管大量减少，可出现（）。

A.生理无效腔气量增大

B.气道狭窄

C.肺组织弹性减小

D.最大通气量降低

E.残气量增加

选择题

如图所示，AB是一质量为m的均匀细直杆，A端靠在光滑的竖直墙壁上，B端置于水平地面上，杆身与竖直方向夹角为θ，杆与地面的摩擦系数为μ，保持平衡，则此时杆与地面的摩擦力为（　　）

A．mgtgθ

B．mgsinθ

C．μmg

D．μmg