A Hypothetical Condition - 仮定法
仮定法過去完了 - Conditional in the Past
仮定法過去完了は、「きちんと勉強しておけば、試験にうかっただろうに」というように、過去の事実とは異なる事をif-節でを言って、主節で事実とは異なる結果の後悔めいた表現をします。
過去の事実とは異なるので、If節は、過去形ではなくさらに一歩さかのぼる、過去完了形。主節は、「〜しただろうに」という表現の"would have"ですね。
If I had studied, I would have passed the exam.
In truth, I did not study, and I did not pass the exam.
If it had not been snow yesterday, we would have gone to the movies.
We wanted to go to the movies, but we did not because of snow yesterday.
ハズレ宝クジを恨めしそうに眺めている人に「宝くじが当っていたらどうした？」と聞く場合は、仮定法過去完了が使えます。
A: What would you have done if you had won the lottery?
B: I would have bought a house.
仮定法過去完了でも、確実性の度合いによって、WOULD ではなく、COULD, MIGHT 使います。
If I had had enough money, I could have bought a house.
could have = would have been able to
If I had had time, I might have gone to the party.
パーティに行くかどうかは、選択肢の一つに過ぎなかった場合
If I had had time, I would have gone to the party.
１００％パーティ行く気持ちがあった場合
