條件句 (If Clauses)
四大類型總覽
| 類型 | 意義 | If 子句 (條件) | 主句 (結果) | 例句 |
|---|---|---|---|---|
| Type 0 | 科學事實/恆真 | 現在式 | 現在式 | If water boils, it turns to steam. |
| Type 1 | 未來可能發生 (真實) | 現在式 | will/can/may + V | If it rains, I will stay home. |
| Type 2 | 現在/未來不可能 (非真實) | 過去式 (be→were) | would/could/might + V | If I were you, I would go. |
| Type 3 | 過去事實相反 (非真實) | had + Vpp | would/could/might + have + Vpp | If I had studied, I would have passed. |
關鍵規則
⚠️ Type 2 be 動詞一律用 were
If I were a bird, I would fly.
If he were here, he would help us.
(口語中 I/he/she 可用 was，考試建議用 were)
⚠️ If 子句不用 will/would
❌ If it will rain, I'll stay home.
✅ If it rains, I'll stay home.
⚠️ 逗號規則
If 子句在前 → 加逗號
If it rains, I will stay home.
If 子句在後 → 不加逗號
I will stay home if it rains.
混合條件句
| 類型 | If 子句 | 主句 | 意義 | 例句 |
|---|---|---|---|---|
| 過去→現在 | had + Vpp (Type 3) | would + V (Type 2) | 過去未做，影響現在 | If I had taken the medicine, I would feel better now. |
| 現在→過去 | 過去式 (Type 2) | would + have + Vpp (Type 3) | 現在特質，影響過去 | If he were smart, he would have solved it. |
替代 if 的結構
Unless = If not
Unless you study hard, you won't pass.
In case (萬一)
Take an umbrella in case it rains.
Were to / Should (正式/可能性低)
Were I you, I'd go. = If I were you...
Should you need help, call me. = If you should need...
倒裝省略 if (正式)
Had I known, I would have come. (= If I had known...)
Were I you, I'd go. (= If I were you...)
虛擬語氣延伸：願望句
| 句型 | 意義 | 動詞形式 | 例句 |
|---|---|---|---|
| wish + 過去式 | 對現在不滿 | V-ed / were | I wish I had a car. |
| wish + 過去完成式 | 對過去後悔 | had + Vpp | I wish I had studied harder. |
| wish + would + V | 希望他人改變 | would + V | I wish you would stop smoking. |
| If only + 同上 | 語氣更強烈 | 同上 | If only I knew the answer! |
| as if/though + 過去/過去完成 | 彷彿... | 同 Type 2/3 | He talks as if he knew everything. |