Good heavens! There you are! We＿＿＿anxious about you, and we ＿＿＿you back throughout the night.

A．are； expect

B．were； had expected

C．have been； were expecting

D．are； were expecting

最佳呼气末正压呼吸（PEEP）的概念是（）。

A.肺顺应性最好

B.萎陷的肺泡膨胀

C.氧分压最高

D.对心排血量影响最小

E.以上都是