完成式不定詞

完成式不定詞多數會出現在第三類條件句,用作完成條件式的一部分;但完成式不定詞也可用在其他句型上。完成不定詞的構成為:
to have + 過去分詞

如同現在式不定詞,有些時候必須用上不帶 to 的被動語態不定詞,因此 to 會被省略掉。這種情況會發生在多數情態助動詞後,以及用在其他使用零不定詞的地方。

舉例
  • He pretended to have seen the film.
  • Before I turn 40, I want to have written a book.
  • I would like to have been to the Taj Mahal when I was in India.
  • If I had known you were coming I would have baked a cake.
  • Someone must have broken the window and climbed in.
  • That man may have noticed the bank robbers' getaway car.