条件文 (if clause)

条件文　＝　前提節　＋　帰結節

条件文の３つの形式

• Type 1
  現在または未来のことの開放条件
  If (present), (future simple/present simple).
• If you go, I will go with you.
• 帰結節が一般的な事実の場合、現在時制を使用する。
  If you heat an ice cube, it melts.

• Type 2
  現在の事実の仮定条件If (past subjunctive), would* + infinitive
• If he went to class, he would learn English.
  彼がクラスに行けば英語を勉強するだろうが
  （事実は彼はクラスに行かない。なので、英語を勉強していない。）

          past subjunctive （仮定法過去）は、be動詞の場合は人称にかかわらず、wereを用いる。

• If she were here, I could explain to her.
• If he were more handsome, I would go out with him.
• If I were you, I wouldn't do that.

• Type 3
  過去のことの仮定条件
  If (past perfect), would* have + V3
• If he had gone to class, he would have learned English.
  もし彼がクラスに行ったならば、英語を勉強していたんだが
  （事実は、彼はクラスに行かなかった。なので、英語を勉強していなかった。）

*wouldの他にはcould/should/might等

練習

• It's raining. I can't do my shopping.
• She won't wear that dress. It doesn't suit her.
• He couldn't go to the party because he wasn't invited.
• She didn't sign the contract because she didn't agree the terms.
• if you lost your books (have to look for them)
• if the flight's postponed (extend my holiday)
• if you come into a lot of money (stop working)
• if all the lights had fused (call an electrician)

ifの省略

ifが省略されて、should, were, had(past perfect)が文頭に出ることがある。

• shouldが文頭に出る場合
• If you arrive before me, please buy the tickets.
• Should you arrive before me, please buy the tickets.
• wereが文頭に出る場合
• If I were you, I wouldn't do that.
• Were I you, I wouldn't do that.
• had (past perfect) が文頭に出る場合
• If he had paid the bill on time, the internet wouldn't have been cut off.
• Had he paid the bill on time, the internet wouldn't have been cut off.

Mixed conditionals

文の内容によって、前提節と帰結節が同じタイプでない場合がある。

• Type 2 + Type 3 [過去の事実の反対 (type 3)]
• If I were you, I would have applied for the scholarship.
• (You were not me, so you did not apply for the scholarship.)

• Type 3 + Type 2 [現在の事実の反対 (type 2)]
• If you had told me earlier, we would be going to the party tonight.
• (You didn't tell me earlier, so we aren't going to the party tonight.)

• Type 2 + Type 1 [現在のことについて (type 1)]
• If they were playing in the field all day, they will be tired now.
• (They were playing in the field all day, so they are tired now.)
• この文は、その日の夜のときで使用する。
  彼らは一日中遊んでいたので、疲れている。