情態(tài)動(dòng)詞表推測(cè)時(shí),該句的反義疑問(wèn)句和情態(tài)動(dòng)詞無(wú)關(guān),必須去掉該情態(tài)動(dòng)詞后,考慮句子謂語(yǔ)動(dòng)詞的發(fā)生時(shí)間和謂語(yǔ)構(gòu)成,再進(jìn)行相應(yīng)的變化.
如：
1.It must have rained last night,didn't it?
去掉must后,考慮時(shí)間狀語(yǔ)last night,說(shuō)明句子本該使用一般過(guò)去時(shí),即變成：It rained last night,所以其反義疑問(wèn)句為didn't it?
再如：
2.You can't have been to Beijing before,have you?
去掉can't后,根據(jù)句意,句子本該使用現(xiàn)在完成時(shí),即變成：You haven't been to Beijing before,所以其反義疑問(wèn)句為have you?