单选题 Man: Where is Joan? She said she would be here at three. And now it"s three-thirty. She must have missed the flight.
Woman: I think so. But I hope she won"t miss the next one. Otherwise she should be late for the opening address of the conference.
Question: What"s the woman worried about?

A、 Joan may have taken a wrong flight.
B、 Joan won"t come to the conference.
C、 Joan will miss the next conference.
D、 Joan may be late for the opening speech.

【正确答案】 D

【答案解析】[解析] A选项“琼很有可能上错了飞机。”B选项“琼不会参加这个会议。”C选项意思是“琼会错过下一个会议。”D选项意思是“琼很有可能赶不上开幕式的演讲。”本题考查了“must have done”这种结构的用法。它表示对过去某种事实的肯定推测。同时从女士话语中，我们可以看出来她很担心琼赶不上会议的开幕式演讲。所以D选项是正确答案。