When we were in the college, we       stay in the library, devoting ourselves to books.

A．should

B．would

C．can

D．need

我国继发性肺动脉高压最常见的原因是（）

A.胸廓畸形

B.弥漫性肺纤维化

C.肺结核

D.慢性肺血栓栓塞症

E.慢性阻塞性肺疾病