Conditional Sentences Type 2

Conditional sentences type 2, 其實以前略為提過：

http://grammarfun101.blogspot.com/2011/08/if-you-went-on-diet.html

先看看一些 type 2 的例子： 

If I were you, I would leave this place at once.
If I had her phone number, I would give it to you.
If he lived near the office, he would be in time for work every day.
If he came here again, I would scream.
If I shaved my head, people would laugh at me. 

在 conditional sentences type 2 中，if-clause 裡的動詞是過去式(past tense)，而 main clause 的動詞是條件式 (conditional tense)。[note: conditional tense = would/should + infinitive/perfect infinitive]

正如以前說過，if-clause 裡的過去式動詞並不是 true past，而是 past subjunctive，用以表達不真實性 (unreality)，或者不可能性 (improbability)。

我們再看看上面的例句： 

If I were you, I would leave this place at once. (but I'm not you; hence, unreal) 

If I had her phone number, I would give it to you. (but the fact is, I don't have her phone number; hence, unreal again)   

If he lived near the office, he would be in time for work. (but the truth is, he doesn't live near the office; hence, unreal)   

If he came here again, I would scream. (but I don't expect him to come here again; hence, improbable)   

If I shaved my head, people would laugh at me. (but I don't intend to shave my head; hence, improbable)

In short, type 2 = unreal, improbable, unlikely, imaginary. 


除了以上的基本句子結構 (if + past + conditional)，conditional sentences type 2 還可以有其他的變異：

1) if + past + might/could   


If you practised more, you might win.
If I knew her address, I could pay her a visit.
If he had a college degree, he could get a job here.

2) if + past + continuous conditional

If I were on vacation now, I would be touring Hong Kong.
If he were bitten by that dog, he would be screaming in pain.

3) if + past + another past （用於表達在過去必然發生的事）

If you stared at that dog, it bit you.

4) if + past continuous

If my car was working, I would drive you to the airport.
It's so hot today!  If we were going by taxi, we would feel much better.