1. Unless you fill the bottle the experiment will work.

The experiment won’t work if you fill the bottle.

2. The computer won’t turn on unless you enter the password.

If you enter the password the computer will turn on.

3. I won’t cover the picnic if the rain gets worse.

I’ll cover the picnic unless the rain gets worse.

4. I hate soap operas. I’ll watch TV with you if you turn to another channel.

Unless you turn to another channel, I won’t watch TV with you.