Exercise 1 Key

1. I can't go on living without you.
2. Give up smoking if you want to live with me. I hate cigarettes.
3. Keep on eating vegetables and fruits if you want to lose weight.

Exercise 2 Key

1. Don't smoke. It's a waste of money.  It's a waste of money smoking.
2. Don't buy the book. There's no point. There's no point buying the book.
3. Don't persuade her. It's a waste of time. It's a waste of time persuading her.
4. Don't see the film. It's not worth it.  It's not worth seeing the film.
5. Don't get angry. It's not worth it. It's not worth getting angry.