英语语法问题healsosaidthathehadfoundfiveemptywhiskybottleswhichtheghostmusthavedrunkthenightbefore.在这句话中,为什么是musthavedone而不是musthaddone?为什么不用过去完成时呢?再问一个问题近义

Question

英语语法问题
he also said that he had found five empty whisky bottles which the ghost must have drunk the night before.在这句话中,为什么是must have done 而不是 must had done?为什么不用过去完成时呢?
再问一个问题 近义词辨析
It occurred to him to open it.He thought____it
a.of opening b.to open c.to have opende d.opening

Answer 1

must had done 在语法上是错误的.没有这种表达方式.
must have drunk 就是过去完成时的表达方式,因为 must 没有“过去时”的形式.must 在这个句子里是作为情态动词（表判断）来使用的.
补充问题：
A 是唯一的选择.前面一句已经说了“他意识到要 open it”,后面一句用 think of opening it 是顺理成章的事.
尚未见过 think 后直接跟不定式的用法.当 think 用作及物动词时,也未见过 -ing 形式直接作宾语的.