【2011山东菏泽】34. —Will you stay for some more days?
—Sorry, I_____. My mother called to ask me to go back at once.
A. mustn’t B. may not C. can’t D. wouldn’t
答案：C
【解析】情态动词表推测。句意：－你再呆几天好吗？－对不起，我不能，我的母亲打电话让我马上回去。Mustn’t禁止；may not可能不；wouldn’t不愿做……，将要不……。故选C。
【2011山东枣庄】25. You ______ wear sports shoes when you climb a mountain.
A. can’t B. shouldn’t C. mustn’t D. have to
