混合条件句
B2 Mixed conditionals 44 / 50
概要
混合条件句连接两个不同的时间：if 条件从句和结果从句指向不同的时刻。做法是从第二条件句和第三条件句里各取相配的一半组合起来——一个分句说过去，另一个说现在。
规则
“纯”条件句里两个分句处在同一个时间框架内：
- 第三条件句 = 过去的条件 -> 过去的结果（想象中的过去）：If I had studied, I would have passed.
- 第二条件句 = 现在的/不真实的条件 -> 现在的结果：If I knew the answer, I would tell you.
当原因和结果发生在不同时间时，混合条件句就会把这两种条件句交叉组合起来。常见的有两种类型。
A 型——过去的条件 -> 现在的结果。 过去（不）真实发生的事，如今仍然影响着现在的情况。
| If 从句（过去） | 结果从句（现在） |
|---|---|
| if + 过去完成时 | would / could / might + 动词原形 |
If I had taken that job, I would be richer now.（我当初没接受那份工作，所以我今天没有变得更富有。）
B 型——现在的/一般性的条件 -> 过去的结果。 关于现在的一个永久性事实或一般性真理，解释了想象中的过去结果。
| If 从句（现在/一般性） | 结果从句（过去） |
|---|---|
| if + 一般过去时 | would / could / might + have + 过去分词 |
If I weren’t so shy, I would have spoken to her at the party.（我是个害羞的人——所以当时才保持了沉默。）
诀窍始终一样：先判断哪个分句说的是过去，哪个说的是现在，再为每个分句选用相应的形式。
形式与结构
| 类型 | If 从句 | 结果从句 | 含义 |
|---|---|---|---|
| A 型：过去 -> 现在 | if + had + 过去分词 | would + 原形 | 过去的原因，现在的结果 |
| B 型：现在 -> 过去 | if + 一般过去时 | would have + 过去分词 | 现在的原因，过去的结果 |
可以把 would 换成 could（能力/可能性）或 might（不确定），分句的顺序也可以自由调换——只要 if 从句放在前面时加上逗号：
- I would be fluent now if I had kept practising.（不加逗号，结果在前）
- If I had kept practising, I would be fluent now.（加逗号，if 从句在前）
当条件即使成立也不会改变结果时，把 if 换成 even if——结果依然不变，常常搭配 still：Even if I had apologised, she would still be angry with me.
B 型现在时分句里用 be 时，正式英语所有人称都倾向用 were：If he were more careful, he wouldn’t have lost it.
B 型的 if 从句里也可以用 could——它是 can 的一般过去时形式，不是 would 形式：If I could drive, I would have taken you to the station.
例句
| English | 说明 |
|---|---|
| If she had set an alarm, she wouldn’t be late right now. | A 型：过去未做的事 -> 现在的后果。 |
| If we had booked earlier, we would be on the beach today. | A 型：过去错过的动作，现在的遗憾。 |
| If I hadn’t missed the train, I would be at the office by now. | A 型：hadn’t + 现在的 would be。 |
| If they weren’t vegetarians, they would have ordered the steak. | B 型：永久性事实 -> 过去的选择。 |
| If he spoke Italian, he would have understood the menu. | B 型：现在的一般能力 -> 过去的结果。 |
| If I were a morning person, I would have come to the early class. | B 型：正式用法中所有人称都用 were。 |
| You could be a doctor now if you had finished medical school. | A 型中用 could 表能力。 |
| If she didn’t hate flying, she might have joined us in Rome. | B 型中用 might 表不确定的过去结果。 |
常见错误
- If I had taken that job, I would have been richer now. -> …I would be richer now. ——结果是现在（此刻）的，所以要用 would + 原形，不用 would have。
- If I am not so shy, I would have spoken to her. -> If I weren’t so shy… ——现在的/一般性的条件要用一般过去时（正式用法用 were），不用现在时。
- If I would have known, I would be upset. -> If I had known… ——if 从句里绝不能放 would。
- If she had been taller, she would have been a model now. -> …she would be a model now. ——把过去的 if 从句和表示现在的 now 混用时，要用 would be，不用 would have been。
- If he weren’t lazy, he would finish it yesterday. -> …he would have finished it yesterday. ——过去的结果要用 would have + 过去分词。
学习提示
- 留意时间标志词：结果从句里出现 now、today、currently 这类词，指向现在的结果（A 型）；yesterday、last week、at the party 则指向过去的结果（B 型）。
- 用你已经学过的两种条件句来搭建：取第三条件句的 if 那一半和第二条件句的结果那一半组合成 A 型，或者反过来组合成 B 型。
- 先判断每个分句各自的时间，再选用形式——不要出于习惯让两半“保持一致”。
- Would have + been = 过去的状态；would be = 现在的状态。判断方法是问自己：“这个结果是在那时成立，还是在现在成立？”