Rewrite the sentences using if and unless, as in the example

If you don't revise early, you won't do well on your exams.

Unless you revise early, you won't do well on your exams.

1. Unless Mr and Mrs Jones leave the house at 9:00 am, they will miss their flight.
2. Unless you learn some stress-management techniques, you won't know how to deal with stress.
3. Unless she gets some rest, she won't be able to continue her work.
4. If we don't hurry, we will miss lunch.
5. Unless I exercise regularly, my body won't stay healthy.
6. If Chloe doesn't study, she won't get good marks.
7. If I don't call, they will be worried.
8. Unless we think positively, the problem will be worse.
9. If Chris doesn't have a stomachache, he should go to school.