(2013·甘肃河西五市一模)Look! The ground is wet. It must have rained last night, ________？

A．hasn't it

B．hadn't it

C．mustn't it

D．didn't it

有关穿刺时气胸并发症，哪一项正确（）。

A.一旦损伤肺尖，均出现呼吸困难

B.经锁骨上进路者发生率为2%～10%

C.局限性气胸，病人可无临床症状

D.经锁骨下进路不容易出现气胸

E.经颈内静脉穿刺可避免此并发症