発展 · Unit 74
仮定法過去
仮定法過去は「If + 主語 + 過去動詞, 主語 + would/could/might + 動詞の原形」の形で、現在の事実と反対の状況を想像して話す表現です。
概念の説明
仮定法過去は「If + 主語 + 過去動詞, 主語 + would/could/might + 動詞の原形」の形で、現在の事実と反対の状況を想像して話す表現です。
A. 形 — If + 過去動詞, would/could/might + 動詞の原形
仮定法過去は if 節に過去時制、主節に would/could/might + 動詞の原形を組み合わせて使う二重構造です。If + 過去動詞, would/could + 動詞の原形 の公式を丸ごと覚えます。
| 構造 | ニュアンス | 例 |
|---|---|---|
| If + 過去, would + 原形 | したい / そうするだろう | If I had time, I would travel. |
| If + 過去, could + 原形 | できるだろう | If I knew French, I could help. |
| If + 過去, might + 原形 | そうかもしれない | If she asked, he might agree. |
- If I lived in Paris, I would visit the Louvre often. (パリに住んでいれば、ルーブルによく行くのに。)
- If we had a bigger house, we could invite more friends. (もっと大きい家があれば、友達をもっと招待できるのに。)
- If you asked her nicely, she might say yes. (彼女に丁寧に頼めば、はいと言うかもしれません。)
- If I spoke Japanese, I would work in Tokyo. (日本語を話せれば、東京で働くのに。)
B. be動詞は were で統一
仮定法過去で be動詞は人称に関係なく were を使うのが原則で、「If I were you」は慣用表現のようによく使われます。会話では was を使うこともありますが、格式や試験では必ず were です。
| 主語 | 原則 (格式) | 会話許容 | 例 |
|---|---|---|---|
| I | were | was | If I were you, ... |
| he / she / it | were | was | If she were here, ... |
| we / you / they | were | were | If they were kind, ... |
- If I were taller, I could reach that shelf. (私がもっと背が高ければ、あの棚に手が届くのに。)
- If he were more careful, he wouldn't make mistakes. (彼がもっと注意深ければ、ミスをしないでしょう。)
- If the weather were nicer, we would go for a walk. (天気がもっと良ければ、散歩に行くのに。)
- If I were in your position, I would take the job. (私があなたの立場なら、その仕事を引き受けます。)
C. 意味 — 現在の事実の反対
仮定法過去は時制上は過去を使いますが、実際には「今」の話をしていて、文の後ろには「(実際は反対だ)」という含意が隠れています。願い・後悔・助言・遠慮がちなお願いをやわらかく伝えるときによく使います。
| ニュアンス | 例 | 隠れた含意 |
|---|---|---|
| 願い | If I had a car, I would drive there. | 今、車がない |
| 後悔 | If I knew the answer, I would tell you. | 今、知らない |
| 助言 | If I were you, I wouldn't quit. | 私はあなたではない |
| 遠慮 (依頼) | If you had a minute, could you help me? | 今、時間がないかもしれない |
| 想像 (反対の事実) | If I were a bird, I would fly everywhere. | 実際は鳥ではない |
| 想像 (ない才能) | If I had her talent, I could become a singer. | 実際は才能がない |
- If I were a bird, I would fly everywhere. (私が鳥なら、どこにでも飛んでいくのに。)
- If I had her talent, I could become a singer. (彼女の才能があれば、歌手になれるのに。)
- If I were you, I would talk to her honestly. (私があなたなら、彼女に正直に話します。)
- If you had a moment, could you check this? (もしお時間があれば、これを見ていただけますか?)
重要ポイント
- 1仮定法過去は時制が過去ですが、実際に指しているのは「今」で、現在の事実と反対の状況を想像する表現です。(例: If I had time, I would go.)
- 2仮定法過去で be動詞は人称に関係なく were で統一するのが原則です。(例: If I were you, ...)
- 3主節には would・could・might の中からニュアンスに合わせて選び、あとには必ず動詞の原形が来るという形の核心を守ります。(例: I would buy / could buy / might buy)
- 4「If I were you, ...」は助言の慣用表現で、会話で非常によく使われるということを覚えておきます。(例: If I were you, I would apologize.)
- 5仮定法過去の if 節の中では絶対に would や will を使わず、過去時制だけを使うというルールを守ります。(例: If I had time, ...)
例文
If I had more time, I would learn Spanish.
もっと時間があれば、スペイン語を学ぶのに。
If I knew her address, I would send a letter.
彼女の住所を知っていれば、手紙を送るのに。
If I were rich, I would travel around the world.
私がお金持ちなら、世界一周をするのに。
If she were here, she would know the answer.
彼女がここにいれば、答えを知っているのに。
If I were you, I would take that job.
私があなたなら、その仕事を引き受けます。
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こんな間違いに注意
If I were you, I would apologize.
If I had time, I would help.
If she knew the answer, she would tell me.
If I had a car, I would drive there.
If he studied harder, he would pass.