1.Study hard or you won't pass the exam

-If you don't study hard ,you won't pass the exam

2.Sarah wants to be a modal but she is short

-Sarah wishes she wasn't short that she was a modal

3.My father spent half an hour repairing my bike

-It took My father half an hour to repair my bike

4.It will take you 50 minutes to go there by bike

-You will take 50 minutes to go there by bike

5.It's twenty years since I visited that town

-I haven't visited that town for twenty years

6.David hasn't smoked for two months

-It's two months since david last smoked

7.I like in a small flat

-I wish I lived in a small flat

8. The astronauts orbited the earth in two hours.

- It took the astronauts two hours to orbit the earth

9. Nobody likes her, do they?

10.Do you know the boy ? He 's playing the guitar

-Do you know the boy who is playing the guitar