情态动词和虚拟语气
1．—Where is Lucy?
—I can't say where she is， but she________ have gone to meet her classmates，for they want to go to Sichuan to work as volunteers.
A．can B．should
C．must D．may
解析：这里表示对过去状况的推断，用“情态动词＋have done”。从前面的“我不确定她在哪里”可知，用may have done，表示“过去可能已经做了……”(不确定)。must have done表示“过去一定做了……”(非常确定)；can have done 用在否定句和疑问句中，should have done 表示“过去本该做……(实际却没做)”。
答案：D
2．If you had brought your swimsuit with you, we ________ swimming in the lake now.
A．could go B．could have gone
C．can go D．have gone
解析：考查虚拟语气。句意：如果你此前带着游泳衣的话，现在我们就可以在湖中游泳了。本句是混合虚拟条件句，前半句是对过去情况的假设，后半句是对现在事实的假设。故选A项。
答案：A
3．—Has Tim started？He said he would join in the party.
—He________ .He is a man of his word.
A．could have left B．must have left
C．can't come D．won't be coming
解析：根据He is a man of his word.可知他是一个守信的人，因此推测他肯定已经启程了。 句意
