问题补充:
—I wonder why Susan looks worried today.
—I’m not sure, but she a small accident driving here.
A. could have
B. might have
C. might have had
D. must have had
答案:
A. could have
B. might have
(答案→)C. might have had
D. must have had
解析:句意为:----我想知道,Susan今天为什么看上去很忧虑呢?----我也不清楚,但是他可能遇到了一点儿小车祸。 由后面的不太确定,可知应为might, 因为他看上去忧虑,所以事情应该发生了,故应为might have done.答案应为C。