They must have ……，——they？A.didnot B.mustnot C.havenot D.have

熱心網友

They must have ……，——they？A.didnot B.mustnot C.havenot D.have 這兒的must have 后面一定是個過去分詞,must have done是用來表示推測的，推測已發生的事，變成反意疑問句時，考慮兩點：如果句中有確切的過去時間，用過去時變， 如果句中沒有確切的過去時間，用現在完成時變．而和must沒關系．　本題你沒寫完整，不知道后面有無過去時間，不能給出答案．但一定是A或C

熱心網友

我認為答案應該是C但是我在取證的時候發現問題了!請看原文以及例題:1:當must表示義務時,附加句仍然是用must you must work hard next term,mustn't you ?2:當must 做必要解時,即可用mustn't,也可用needn't。you must go home right now ,mustn't you /needn't you ?3:當must 做一定\想必等推測性意義時,附加句部分仍用must。例句如下he must be very tired,mustn't he?在這種語境下,間或也可根據上下文采用其他動詞。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 ?我參考的是第四版主編章振邦所以答案就可能是ABC全對啊請高手指點一二。

熱心網友

答案選C