They must have ……，——they？A.didnot B.mustnot C.havenot D.have
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They must have ……，——they？A.didnot B.mustnot C.havenot D.have 这儿的must have 后面一定是个过去分词,must have done是用来表示推测的，推测已发生的事，变成反意疑问句时，考虑两点：如果句中有确切的过去时间，用过去时变， 如果句中没有确切的过去时间，用现在完成时变．而和must没关系． 本题你没写完整，不知道后面有无过去时间，不能给出答案．但一定是A或C
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我认为答案应该是C但是我在取证的时候发现问题了!请看原文以及例题:1:当must表示义务时,附加句仍然是用must you must work hard next term,mustn't you ?2:当must 做必要解时,即可用mustn't,也可用needn't。you must go home right now ,mustn't you /needn't you ?3:当must 做一定\想必等推测性意义时,附加句部分仍用must。例句如下he must be very tired,mustn't he?在这种语境下,间或也可根据上下文采用其他动词。例如he must be very tired ,isn't he?he must have waited here for a long time ,hasn't he ?you must have seen the play last week ,didn't you ?我参考的是第四版主编章振邦所以答案就可能是ABC全对啊请高手指点一二。
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答案选C