瘘管的特点是（） A.多伴有剧痛 B.脓水淋漓不止 C.病理性盲管 D.有内外两口

I think your bike needs ________．  [ ]

A. repair      

B. repaired  

C. to repair    

D. repairing

Man: The snow is really coming down, isn't it Woman: Rarely do we get so much snow in December. Question: What does the woman mean

A．It's typical December weather for this region.

B．It won't really snow until December.

C．Such a large amount of snow is unusual for this month.

D．There has never been much snow down South.

地震灾区重建过程中，工人用图示的滑轮组将重400N的建筑材料从地面缓慢提升至l0m高处。已知该工人对绳子的拉力为250N，则此过程人做的总功为_____________J，该滑轮组的效率为__________%。

正常小儿后囟闭合的时间一般于生后（）

A.3～5周

B.6～8周

C.9～11周

D.12～14周

E.15～18周

深井泵的扬水管由多节管组成，它们之间用联轴器连接。