4/ You must leave home early or you’ll miss the flight.
à If you don’t ​leave home early, you'll miss.....
5/ I was busy, so I didn’t have enough time to go to the market.
à If I hadn’t been busy, ​i would have enough time....( đk loại 3) 
6/ I’d like to buy a new car, but I haven’t got enough money.
à I would ​like buy a new car, if i had got enough money 
7/ If you don’t study, you’ll fail your English exam.
à Unless ​you study, you'll fail your english exam ( unless= if not) 
8/ You’re tired because you go to bed late.
à If you ​were tired, you would go to bed early 
9/ It was so cold yesterday that we stayed at home.
à We wouldn’t have stayed at home if ​it had been so cold yesterday 
10/ I didn’t take any pictures because I forgot my camera at home.
à Unless I brought along my camera, ​ i would take any pictures ( unless= if not ) 

4) if you don't leave home early, you will miss the flight.

5) if I hadn't been busy, I would have had enough time to go to the market.

6) i would buy a new car if i had enough money

7)unless you study, you will fail your english exam

8) if you went to bed early, you wouldn't be tired

9) we wouldn't have stayed at home if it hadn't been so cold

10) unless I brought along my camera, I could take some pictures.