1) Keep silent or you'll wake the baby up.
-> If you don't keep silent, you'll wake the baby up.
2) Because you don't leave immediately, I call a policeman. 
-> If you leave immediately, I won't call a policeman.
3) I don't know the number, so I don't ring her up.
-> If I knew the phone number, I would ring her up.
4) Go right now or you'll be late for the train.
-> If you don't go right now, you'll be late for the train.
5) As she is often absent from class she can't keep pace with her classmate.
-> If she weren't often absent from class, she could keep pace with her classmate.
6) I couldn't write to Alice beacuse I did't know her address
-> If I had known Alice's address, I could have written to her.
7) I don't know the answer, so I can't tell you.
-> If I knew the answer, I could tell you.
8) The heavy rain kept everybody from going out 
-> If the rain wasn't heavy, everybody could go out.
12) This chair is too heavy for him to move 
-> If this chair wasn't too heavy, he could move
13) He had a flu beacuse he went out in the rain last night
-> If he hadn't gone out in the rain last night, he wouldn't have a flu.
14) Stop talking or you won't understand the lesson
-> If you don't stop talking, you won't understand the lesson
15) The fridge keeps the food from spoiling
-> If we don’t keep food in the fridge, it will be spoilt 

1. I dont' t understand the lesson
=> I wish....
2. My relatives live far from me
=> I wish.....
3. My sister eats little food
=> I wish.......
4. Nam always draws on the wall
=> I wish.....
5. Viet Anh talks too much in class
=> ...wish...

1. Keep silent or you'll wake the baby up.
> if you dont keep silent,you'll wake the baby up
2.Because you don't lêav immediately, I call a policeman. 
> if you leave immediately, I wont call a police
3.I don't know the number, so I don't ring her up.
>if I knew the phone number, I would ring her ụp
4. Go right now or you'll be late for the train.
> unless you go right now, you'll be late for the train.