Conditional Sentences

條件句子

條件句子由兩部分組成， main clause 和 if-clause.

有3種類型的條件句子。

Type I: real conditions "If the weather is good tomorrow, we will go hiking."

Type II: unreal conditions "If I was a bird, I would fly in the sky."

Type III: unreal conditions in the past "If you had told me before, I would have helped you."

Type 1

第一種類型的條件句，表示一種可能性。適用於現在或者將來。先陳述條件，在這種情況下，某件事會發生。比如， 如果明天不下雨，我就去打球。"If the weather is good tomorrow, we will play basketball."

形式： if clause + main clause.

main clause 可以是 3種情況： will-future, or a clause with a modal verb and an infinitive, or an imperative.

If I arrive in time, …

… I willcome and help you. （will-future）

… I could talk to him personally. (modal verb and an infinitive)

… please wait for me at the door.

大部分這種句子，都是跟一個 will-future的主句。 如：

• If the weather is good tomorrow, we will go swimming.
• If you are hungry, we will stop by a restaurant.
• If the children behave well, they will be allowed to visit their friends.
• If you drive to fast, you will cause an accident.

if-clause 是一般現在時 simple present.

Type 2

第二種類型的 條件是 永遠不可能是真的。比如，如果我會飛，我就不用你坐電梯了。

其中if-clause 是用 simple past .一般過去式 ，來表示這種感覺。 但它的 main-clause 是作用於 現在 和 未來。

構成方式：

They are formed by an if-clause in simple past and a main clause with would/could/might + infinitive.

例如：

If I was a famous sports-man, I would be very rich.

If Lara was not that arrogant, we would get along very well.

If your shoes were not that dirty, you could leave them on in the house.

If I was an animal, I would like to be a cat.

Type 3

第三種類型 ，是一種後悔的話，if中的假設是過去的事情。比如。如果我去年買了比特幣的話，現在就大賺了。 所以這種 if 也是 的假設也是 never become real 。

形式：

If-clause in the past perfect + main clause with "would/could/might" + "have" + past participle

if clause 中是 過去完成時 ， main-clause 中是 would + have + -ed。

例句

If I had not sold out my Bitcoin last year, I would have been able to buy a house. (But I sold it all.)

If it had not rained all day, we would have gone on a bike tour. (But it rained all day and we did not go on a bike tour.)

If Martha had told me that before, I could have been there at the right time. (But she did not tell me, and I was too late.)

更多例句

If I had known how to drive, I would have gone there by car.

If I had gone to the shop, we would have enough milk.

If I had hurried at breakfast, I would not have missed the bus.

參考：

Conditionals (If-Clauses) - Learning English Online

Conditionals (If-Clauses): Type I

Conditionals (If-Clauses): Type II

Conditionals (If-Clauses): Type III

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