问题
选择题
(2013·济南一中模拟)—Where ________ Mary have put the empty bottles?
—She ________ them away. They must be somewhere.
A．can; can't have thrown
B．must; needn't
C．must; must have thrown
D．can; mustn't have thrown
答案
答案：A
选A 句意：“玛丽可能把空瓶子放在什么地方了？”“她不可能扔掉，瓶子一定在某个地方。”第一空在疑问句中表示可能性用can；第二空表示“不可能做过某事”用can't have done，注意不能用mustn't表示推测。
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