1. It's a pity I didn't take my doctor's advice.

=> I wish I took my doctor's advice.

2. If they don't tell me the problem, I can't help them.

=>Unless they tell me a problem, I can't help them.

3. They didn't play well, but they won the game.

=>Although they didn't play well,but they won the game.

4. It's 3 years since I last saw Nam.

=>I haven't saw Nam for 3 years

5. "Let's go out for a walk " said Mrs. Hoa.

=>Mrs.Hoa suggested me to go out for a walk.

Xin hay nhất

1.

=> I wish I took my doctor's advice.

2. 

=>Unless they tell me a problem, I can't help them.

3.   

=>Although they didn't play well,but they won the game.

4. 

=>I haven't saw Nam for 3 years

5. 

=>Mrs.Hoa suggested me to go out for a walk.