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Câu điều kiện (Conditional sentences)

I. Present probable conditions (điều kiện có thể xảy ra ở hiện tại)

If clause (Mệnh đề if) Main clause (mệnh đề chính)
Simple present

shall/will

can                 + Verb (without To)

may

Ví dụ:

- If you do your best, you can pass the test.

- If you do not hurry, you may miss the train.

- You will fail in your examination if you do not work hard.

II. Present unreal conditions (điều kiện không có thật hoặc không thể xảy ra ở hiện tại)

If clause (Mệnh đề if) Main clause (Mệnh đề chính)

- Simple past

- Nếu là BE: dùng WERE cho tất cả các ngôi

should / would

could       + Verb (without TO)

might

Ví dụ:

- If I were she, I should marry him.

- If I had money, I shoud give it to him.

III. Past unreal conditions (điều kiện không có thật hoặc không thể xảy ra ở quá khứ)

If clause (mệnh đề if) Main clause (mệnh đề chính)
Had + past participle

should / would

could                + have + past participle

might

Ví dụ:

- If I had had money, I should have given it to him yesterday.

- If he had known that I was ill, he would have come to see me yesterday.

- If you had left earlier, you would have caught the train.

Lưu ý:

+ "HAD + PAST PARTICIPLE" ở mệnh đề phụ có thể thay bằng "COULD HAVE + PAST PARTICIPLE".

Ví dụ:

- If I had come, she would have been very happy.

-> If I could have come, she would have been very happy.

+ Có thể dùng đảo ngữ trong PRESENT UNREAL CONDITIONS và PAST UNREAL CONDITIONS.

Ví dụ:

- If I were a doctor...

-> Were I a doctor...

- If she were to go home...

-> Were she to go home...

-> Should she go home...

- If she had money...

-> Did she have money...

- If I had known him...

-> Had I known him...

UNLESS = IF NOT

- Uncless there is enough rain, rice won't grow.

-> If there isn't enough rain, rice won't grow.