一I still cannot figure out why he missed his flight．一He an accident on the way to the airport．A.could have hadB.should have hadC.would haye hadD.must have had
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A解析考查情态动词和虚拟语气。“我仍然不理解他是怎么错过航班的。”“他可能在去机场的路上遇到事故了。”could have done表示不太肯定的推测，“可能已经做了某事”；should have done“本应该做某事”；D“一定已经做了某事”。根据答语可知，表示的是不太肯定的推测。故选A。