仮定法過去完了（第三条件文）

仮定法過去完了（第三条件文）の形は if + had + 過去分詞（過去完了形）、would have + 過去分詞 です。過去が違っていたらと想像するときに使います — すでに起こったことなので、条件も結果も現実ではありません。

短縮形：If I'd known（had）、I'd have come（would）、I would've come。速く話すと、would have は「would-ə」のように聞こえます。

💡if 節の 'd は had（If I'd known）、結果の節の 'd は would（I'd have gone）です。また would've は「would of」のように聞こえるので、スペルを間違える人がよくいます — 書くときは必ず would have です。

1. 違う過去を想像する — 実際に起こったのはその反対

• If I had left earlier, I wouldn't have missed the train.

  もっと早く出ていれば、電車に乗り遅れなかったのに。（実際は遅く出て、乗り遅れた）

• If Lan hadn't helped me, I would have failed the course.

  ランが助けてくれなかったら、その授業は落としていたでしょう。（実際はランが助けてくれた）

2. 過去のことへの後悔や非難

• If you'd told me it was your birthday, I'd have bought you a cake.

  誕生日だと言ってくれていたら、ケーキを買ってあげたのに。

• We would have won if we hadn't made so many mistakes.

  あんなにミスをしなければ、私たちは勝っていたでしょう。

3. 悪いことが起こらなくてよかったという安堵

• If the neighbours hadn't smelled the smoke, the whole house would have burned down.

  近所の人が煙のにおいに気づかなかったら、家が丸ごと焼けていたでしょう。

• If you hadn't reminded me, I would have forgotten my passport.

  あなたが言ってくれなかったら、パスポートを忘れるところでした。

結果の節では would の代わりに could have + V3（= would have been able to、〜できただろう）や might have + V3（= would perhaps have、〜したかもしれない）も使えます。

• If we'd booked earlier, we could have sat together.

  もっと早く予約していれば、隣同士で座れたのに。（could have = would have been able to）

• If she had applied, she might have won the scholarship.

  彼女が応募していたら、奨学金をもらえたかもしれません。（might have = would perhaps have）

それぞれの節がいつのことかを考えましょう。過去のことを言う節 → had V3 / would have V3、今のことを言う節 → 過去形 / would + 動詞の原形。2つの節の時が違うと、混合条件文になります。

• If I had studied medicine, I would be a doctor now.

  あのとき医学を勉強していたら、今ごろ医者になっているでしょう。（過去 → 現在）

• If we hadn't moved to Da Nang, we wouldn't know each other.

  ダナンに引っ越していなかったら、私たちは知り合っていないでしょう。（過去 → 現在）

• If he were more organised, he wouldn't have forgotten the meeting.

  彼がもっときちんとした人なら、会議を忘れなかったでしょう。（現在 → 過去）

• If I didn't have to work tomorrow, I would have stayed at the party longer.

  明日仕事がなければ、パーティーにもっと長くいたのに。（現在 → 過去）

💡混合 1 の結果の節には now、today、still がよく出てきます。「now」があって if 節が had V3 なら、結果は would have ではなく would + 動詞の原形 です。

改まった英語では、if を省いて had を主語の前に置くことができます：Had I known = If I had known。否定は Had … not + V3 です（Hadn't I… と短縮しません）。レッスン「倒置」を参照してください。

• Had we known the road was closed, we would have gone another way.

  道路が通行止めだと知っていたら、別の道を行ったでしょう。

• Had she not called, I would have waited all night.

  彼女が電話してくれなかったら、私は一晩中待っていたでしょう。（Hadn't she called ではない）

• ✗If I would have known, I would have come.

  ✓If I had known, I would have come.

  if 節は had + V3 です。「If I would have…」はくだけた会話で耳にしますが、標準的ではありません。

• ✗If I knew you were in hospital, I would have visited you.

  ✓If I had known you were in hospital, I would have visited you.

  過去のことなので had known です。

• ✗We were late. If we had taken a taxi, we would arrive on time.

  ✓We were late. If we had taken a taxi, we would have arrived on time.

  結果も過去のこと → would have + V3 です。

• ✗If she had took the medicine, she would have felt better.

  ✓If she had taken the medicine, she would have felt better.

  had + 過去分詞（taken）です。過去形は使いません。

• ✗If she had asked me, I would of helped her.

  ✓If she had asked me, I would have helped her.

  would've は「would of」のように聞こえますが、必ず have です。

• ✗If it had not rained, we would have play tennis.

  ✓If it had not rained, we would have played tennis.

  would have + 過去分詞です。