--- Where are the students ? How could they keep us waiting for so long? 

--- They started an hour ago and they____ be here in fifteen minutes, I think.

A．might

B．would

C．should

D．must

修船时大副在何种情况下会同船长、轮机长检查船壳和水线以下各种装置（）。Ⅰ．航修时；Ⅱ．出坞前；Ⅲ．进坞后。

A.Ⅰ、Ⅲ

B.Ⅰ～Ⅲ

C.Ⅱ、Ⅲ

D.Ⅰ、Ⅱ