1. If I don't buy a new hat, I will not give it to you
2. If today were not sunday, the pupils could not go swimming
3. If he had not been here, he would not have had a lot of fun
4. If my brother does not enough money, he will not buy a bicycle
5. If he had not had enough time, he would not have read this novel
6. If she had not missed the bus, she wouldn't have been late
7. If Peter doesn't study hard, he could not have good marks
8. If my sister had a terrible headache, she would be absent from her class
9. If Windy had came, we would not have cancelled this the meeting
10.If he hadn't been angry, he would have said anything.
Loại 1
If + hiện tại đơn , S + will/can/may + V + ..
Loại 2
If + quá khứ đơn , S + would / might / could + V + ..
Loại 3
If + quá khứ hoàn thành , S + would + have + `V_{II}`