—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
网友回答
(答案→)A. can; can’t have thrown
B. must; needn’t
C. must; must have thrown
D. can; mustn’t have thrown
解析：考查情态动词ｃａｎ的用法：ｃａｎ＋完成时，表示推测的时候，ｃａｎ用于疑问和否定句，第一空是用于疑问句，用ｃａｎ，第二空是用于否定句，ｃａｎ＇ｔ ｈａｖｅ ｄｏｎｅ过去不可能做了什么，句意：玛丽把空瓶子放在哪里呢？――她不可能扔了的。一定在什么地方。选Ａ。