Ex5.

1. Unless you study hard, you will fail the exam.

2. Unless you like this one, I'll bring you another.

3. Unless she hurries, she will be late.

4. Unless you're careful, you will cut yourself.

5. Unless you sneezed, he wouldn't have known that we were there.

6. Unless you work harder, you will be sacked because of your laziness.

7. Unless there had been the heavy storm, the climbers will not have died.

8. Unless she tried her best to do it herself, nobody can help her.

9. Unless you know how to spell a word, you should look it up in the dictionary.

10. The campfire would have been cancelled unless it rained last night.

Ex6.

1. B. will buy

2. C. had driven

3. A. would win

Ex8.

1. will reduce-> reduce

2. Unless-> If

3. continue-> continued

4. am-> were

5. could find-> found 

6. ran-> would run

7. could speak-> spoke

8. is not-> wasn't

9. were-> was

10. will-> would 

Ex9.

1. had been-> were

2. doing-> to do

3. Unless-> If

4. I known-> known

5. when the-> the

6. can go-> could have gone

7. confident-> confidently

8. had had-> had

9. Had I known-> Did I know

10. would stop-> would have stopped

Ex10.

1. You should make a trip to England.

2. Unless he wasted too much time, he wouldn't have failed in his examination last year.

3. We didn't buy the car yesterday because it wasn't large.

4. You should save some of your lottery winning.

5. I didn't take the English course you offered so I wouldn't make much progress.

6. Unless my grandmother were five years younger, she wouldn't play game with us.

7. Unless you had been so busy lately, I would have shown you how to play bowling.

8. If those curtains were blue, your room would look better.