Havinghad用法请详细讲解一下havinghad的用法,主要作句首的作用还有Tohavehad的用法,以及与havinghad有什么区别,

Question

Having had用法
请详细讲解一下having had的用法,主要作句首的作用
还有To have had的用法,以及与having had有什么区别,

Answer 1

这两个have是不同的,前一个是助动词 无词义只表示完成.后一个是行为动词有它自己的词义,不同的句子里意思不同.有吃,进行等意思.如
Having had breakfast,Tom went to school.吃完早饭,汤姆去上学了.（表示吃的动作发生在上学之前所以用了现在分词的完成时）
Tom seemed to have had his breakfast.(汤姆好像吃过早饭了)因为seem后必需接不定式to do这里又表示吃的动作发生在谓语动作之前所以用不定式的完成式.
在以下词后有用不定式to have had的时候.
句型主语be +过去分词+to have had
eg,Tom was said to have had his exam.
或用在 pretend ,seem appear之后.
Tom pretended to have had his supper.