—I wonder why Suzan 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
网友回答
A. could have
B. might have
(答案→)C. might have had
D. must have had
解析：既然是I'm not sure不确信，应该用might来表达推测，后面给出的时间状语是driving here开车来时，所以用might have had。