He must have stayed up late last night,didn't he 这里为什么用didn'

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He must have stayed up late last night,didn't he 这里为什么用didn't he不用haven't he
是 hasn't he

must表示推测的时候要根据意思而不是根据形式来完成反义疑问句.must have +过去分词表示对过去的推测：他昨晚一定熬夜了,不是吗?推测过去,要用过去时态didn‘t
而不用must的肯定或否定形式.
再如：The boy must be Li Ming,isn't he?不用must
再问：如果把上句中的 must 去掉，还成立吗。
再答：去掉must 就不是表示推测了。就违背了原句的意思。

请教：He must have stayed up late last night,_____? A.didn't he He must have done his homework last night,didn't he? 这里为什么用d he must have finished his homework last night,didn't he?为什么是 he must have stayed up late night,__he? （）——He didn't stay up late last night. He stayed at home last night.He didn't go to the cinema.(保持原 wangcheng looked tired because he stayed up late last night He ____ sleeping pills last night.He didn't wake up till lun he didn't go to bed until very late last night=he__ __late l He didn't go to bed until very late last night.(同义句转换) He didn't have breakfast ,___ he got up late.A.because B he didn't do his homework last night,so he did .还是so he didn