`Đáp` `án:` 

6. If he didn't smoke too much, he could get rid of his cough.

7. If she hadn't walked to the meeting, she wouldn't have been late.

8. If I had eaten lunch, I wouldn't feel hungry now.

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If 2:

If + S + were , S + would / could + V1 

If + S + V2/ed , S + would / could + V1 

--> Câu điều kiện không có thật ở hiện tại

If 3:

If + S + had + V3/ed , S + would / could + have + V3/ed

--> Câu điều kiện không có thật trong quá khứ 

If hỗn hợp loại 1: If + S + had + V3/ed, S + would/ could+ V1