has had 和had had有什么区别?

如题所述

第1个回答  2019-05-02
一个是现在完成时,一个是过去完成时
he
has
been
worked
in
hospital
表示他过去在医院工作,现在有可能还在医院工作
单数或第三人称时用has
they
have
been
worked
in
hospital
人称复指,第一二人称时用have
he
had
been
worked
in
hospital
他过去在医院工作,现在不在了
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