type1 and type 0

Type 0: 講科學定理, 自然定律, 兩面用 simple present tense 表示:
If water boils, it turns into steam.
If water freezes, it becomes ice.

Type 1: 講未來會發生既事, 未必100%發生, 但機會幾高, If 後面用simple present tense, 另一句用 simple future:
If he comes, she will go away.
If they are here, I will be happy.

如果句子調轉寫, tense 亦要跟住走:
She will go away if he comes.
I will be happy if they are here.

***will 亦可寫成 may 或 can

If he comes, I may leave.
If the phone rings, can you answer it?



2010-06-05 08:17:34 補充：
如想知其他 if 既類型, 可參考我既另一文章:
http://hk.knowledge.yahoo.com/question/question?qid=7010060500044

我推薦您一個非常不錯的英語學習網站，里面有很多非常不錯的學習資源：

http://www.hkenglishstudy.info

希望可以幫到你!

I'm not really sure which two types you meant. So I'll show you all about the Conditionals.



There are totally 4 main types.

1. If + present :

We use this type to describe something about facts.

E.g. If you heat water to 100 degrees centigrade, it boils.
E.g. If/When the thermometer is at 0 degree centigrade, water freezes.
(It is a fact.)


2. If + future :

We use this type to show a possibility of some cases.

E.g. If I find it, I will tell you.
(In this example, 'I' feel there is a possibilty that I can find something so I use present tense.)


3. If + past :

We use this type to talk about imagination. That means something is not going to happen or it will not be possible to happen.

E.g. If I were you, I would tell her the truth.
(In this case, I cannot be you so this situation is not real. I just pretend that I were you.)


4. If + past perfect :

We use this type to show our remorse or regret.

E.g. If I had known you were in the hospital, I would have gone to see you.
(We cannot change the situation so we use this type when we want to express our regret of incident occured.)