--- 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
网友回答
A. might
B. would
(答案→)C. should
D. must
解析:should在这里表示预期,“应该会,可能”。can表示有能力做或能够发生;would表示想象中的结果;must表推测,或表必须。