1. If they behave themselves, their parents will be happy about that.

2. If she had said sorry, he wouldn't have been angry.

3. If I were a rich businessman, I could afford to buy an expensive car

4. If it hadn't rained last night, I would have gone to the barbecue.

5. If my parents allowed me to go, I wouldn't have to stay at home.

6. If she paid attention to her cooking, the food wouldn't be horrible.

7. If the weather hadn't been very nice, we wouldn't have gone camping.

8. If the computer hadn't broken down, I wouldn't have to stop my work.

9. If she didn't love him, she wouldn't forgive him easily.

10. If he hadn't been angry, I would have said something.

1. they don't behave themselves so their parents are not happy about that

-> if they behaved themselves, their parents would be happy about that.

2. she didn't say sorry so he was angry

-> if she had said sorry, he wouldn't have been angry.

3. i am not a rich businessman and t can't afford to buy an expensive car

-> if I was a rich businessman, I could ( afford to ) buy an expensive car.

4. it rained last night so i didn't go to the barbecue

-> if it hadn't rained last night, I would have gone to the barbecue.

5. my parents do not allow me to go, so i have to stay at home

-> if my parents allowed me to go, I wouldn't ( have to ) stay at home.