问题
选择题
— How could they keep us waiting for so long?
— They got on the bus half an hour ago and they ________ be here in ten minutes, I think.
A．might
B．would
C．should
D．must
答案
答案：C
考查情态动词。句中should表示“应当”之意：——他们怎么能让我们等这么久呢？——他们半个小时前上公共汽车，我想他们应当10分钟内到达这里。