—I wonder why Mr Green hasn't showed up at the meeting yet.—I'm not sure but hein a traffi

问题补充：

—I wonder why Mr Green hasn showed up at the meeting yet.

—Im not sure，but hein a traffic jam driving here.

A. could be stuck

B. might have been stuck

C. might be stuck

D. must have been stuck

答案：

A. could be stuck

(答案→)B. might have been stuck

C. might be stuck

D. must have been stuck

解析：句意：——我想知道为什么格林先生还没有出现在会议上。——我不确定,但是他可能开车来这里的路上遇到了交通堵塞。根据hasn showed up可知格林先生现在还没有出现，那他遇到交通堵塞应在现在之前，过去的时刻，情态动词+have+done表示过去，因此排除AC。must 表示又把我的推测“一定”，might表示没有把我的推测，“也许，可能”，根据 Im not sure我不确定，选B。