问题补充:
My aunt here by now, for she took the early bus.
A. must arrive
B. can arrive
C. may arrive
D. ought to have arrived
答案:
A. must arrive
B. can arrive
C. may arrive
(答案→)D. ought to have arrived
解析:ought to除了可以跟should一样表示“应该”之外,还可以表示推测,“照理应该”,而must表示相当肯定的语气,“一定;必定”,本题还着重考查正确使用时态,表示到目前应该已经发生用ought to +完成时态。