1 . Unless he wastes so much time in games , he will make a good progress in his study.

2 . If she doesn't speak English as well as you do , Lan will be not happy

3 . Unless he often stays up late to watch football matches,he won't feel very tired

4 . If he drives carefully, he  won't have many accidents

5 . If my uncle knows how to drive , he will buy a car

1. Because he wastes so much time in games, he doesn’t make a good progress in his study.

→ Unless he wastes so much time in games, he will make a good progress in his study

2. Lan is not happy because she doesn’t speak English as well as you do. 

→If  Lan spoke English as well as you do, she would happy.

3. He often stays up late to watch football matches, so he feels very tired. 

→Unless he stays up late to watch football matches, he will feel very tired.

4. Because he doesn’t drive carefully, he has many accidents.

→ If he drove carefully, he wouldn't have many accidents.

5. My uncle doesn’t know how to drive, so he doesn’t buy a car.

→If my uncle knew how to drive, he would buy a car.