Lesson 2

I think you should stop smoking.

1. If I am you, I will stop smoking. 
2. If I were you, I will stop smoking.
3. If I were you, I would stop smoking. 
4. If I had been you, I would stop smoking.

If you take the ice out of the fridge, it …………………

1. vaporizes
2. melts
3. heats 
4. disappears

We should do something to protect water from being polluted ………… we will have nothing to drink in the future.

1. if
2. whether 
3. or
4. unless

Let’s knock on their door to see ……… home.

1. if they’re
2. unless they’re
3. whether they were 
4. if they were