—I wonder why Suzan looks worried today.—I’m not sure but she a small accident driving he

问题补充：

—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

答案：

A. could have

B. might have

(答案→)C. might have had

D. must have had

解析：既然是Im 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。