Câu điều kiện
1. Be careful; otherwise you will fall.
Unless you are careful, you won't fall.
2. Because you don’t leave immediately, I call a policeman.
Unless you you leave, I won't call a policeman.
3. I didn’t know her number, so I didn’t call her.
If I known her number I will call her.
4. The heavy rain kept every body from going out.
If the rain kept heavy every body would have gone out.
5. Without the air, we would die.
Supposing that without the air, we would die.
As long as/ Providing that without the air, we will die.