如何分conditionals type 0-3?

0. General conditionals
用法：用於講事實, 不變定律等等

句式：
if-clause: present simple
main clause: present simple

例子：
a. If we eat contaminated food, we become ill.
b. If we boil water to 100oC, it changes into steam.

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1. Open present or future conditionals
用法：有可能發生之事

句式：
if-clause: present simple
main clause: will + infinitive without to

例子：
a. If you want to read the book, i will lend it to you.
b. If it rains tomorrow morning, we will cancel our picnic.

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2. Unreal present of future conditionals
用法：不可能發生之事(現在/將來)

句式：
if-clause: past simple
main clause: would + infinitive without to

例子：
a. I am busy now. If i had time, i would help you.
b. I don't have a car. If i had one, i would take you for a ride.

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3. Unreal past conditionals
用法：不可能發生之事(過去)

句式：
if-clause: past perfect
main clause: would + have + past participle

例子：
a. If we had taken the 7:20 ferry, we would have been involved in the accident.
b. If the driver had been driving slowly, he would have been able to stop in time to avoid the accident.

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If Type 0