仮定法過去完了形

形状

仮定法過去完了形の文章では、 'if' 節の時制は過去完了形で、主節の時制は条件付完了形あるいは条件付完了継続形です。

If 節 (条件)	主節 (結果)
If + 過去完了形	条件付完了形あるいは条件付完了継続形
If this thing had happened	that thing would have happened.

すべての条件文と同様、文節の順序は決まっていません。代名詞を置き換えたり、句読点を調節しなければならない場合がありますが、意味は同じです。

例

If it had rained, you would have gotten wet.
You would have gotten wet if it had rained.
You would have passed your exam if you had worked harder.
If you had worked harder, you would have passed your exam.
I would have believed you if you hadn't lied to me before.
If you hadn't lied to me before, I would have believed you.

機能

仮定法過去完了形は、過去の不可能な条件とそれから起こりえる過去の結果を述べます。こうした条件や結果が起こることは今となっては不可能ですので、これらの文章は全くの仮説で現実ではありません。仮定法過去完了形には、常に後悔の気持ちが潜んでいます。現実は、文章が述べることとは逆あるいは正反対です。仮定法過去完了形は、過去を指し、仮説を述べています。

例

If I had worked harder I would have passed the exam. (But I didn't work hard, and I didn't pass the exam.)
If I had known you were coming I would have baked a cake. (But I didn't know and I didn't bake a cake.)
I would have been happy if you had called me on my birthday. (But you didn't call me and I am not happy.)

仮定法過去完了形の文章では、"would" の代わりに叙法を用いて、結果の確信、了承や提案の度合いを表現することもできます。

例

If I had worked harder I might have passed the exam.
You could have been on time if you had caught the bus.
If he called you, you could go.
If you bought my school supplies for me, I might be able to go to the park.

縮約

wouldとhad は、どちらも 'dに縮約することが出来ます。仮定法過去完了形の文章に自信がない場合紛らわしいものですので、以下の二つの規則を覚えて置いてください：
1. would は if-節には現れませんので if 節に'd があれば、これは hadの短縮です。
2. had は、never appears before haveの前には来ませんので、'd がhaveの前の代名詞についていたら、これは wouldの短縮です。

例

If I'd known you were in hospital, I'd have visited you.
If I had known you were in hospital, I would have visited you.
I'd have bought you a present if I'd known it was your birthday.
I would have bought you a present if I had known it was your birthday.
If you'd given me your e-mail, I'd have written to you.
If you had given me your e-mail, I would have written to you.

条件付完了形の時制

すべての動詞の条件付完了形は三つの要素からなります：
would + have + 過去分詞
後に過去分詞が続くHave は、他の構文にも使われ "完了不定詞"と呼ばれます。

主語	+ would	+ have	+ 過去分詞
He	would	have	gone
They	would	have	stayed

To Go：条件付完了形

肯定文	否定文	疑問文	否定疑問文
I would have gone	I wouldn't have gone	Would I have gone?	Wouldn't I have gone?
You would have gone	You wouldn't have gone	Would you have gone?	Wouldn't you have gone?
He would have gone	He wouldn't have gone	Would he have gone?	Wouldn't he have gone?
She would have gone	She wouldn't have gone	Would she have gone?	Wouldn't she have gone?
We would have gone	We wouldn't have gone	Would we have gone?	Wouldn't we have gone?
They would have gone	They wouldn't have gone	Would they have gone?	Wouldn't they have gone?