Rewrite
1. I haven't seen that man before.
→→ It's the first time I have ever seen that man
2. She had never been so unhappy before.
→→ She was unhappier than she had been before
3. He left school and then joined the army.
→→ After having left the school ,he joined the army
4. Maria says she'd like to have been put in a higher class.
→→ Maria wishes she had been put in a higher class.
5. Would you like me to finish the work tonight ?
→→ I'll finish the work tonight if you like
6. You may get hungry on the train so take some sandwiches.
→→ In order to not get hungry on the train,take some sandwiches.
7. " I don't think John will come " said Bill.
→→ Bill doubted whether John would come or not
8. I don't suppose you have change for a pound, do you ?
→→ Do you happen to have change for a pound, do you ?
9. She asked Michael how she liked her new dress.
→→ " How do you like your new dress"-she asked michael
10. A train leaves at 8 o'clock every morning.
→→ There is a 8-oclock train leaving every morning.
11. Nobody can deny that she has a beautiful voice.
→→ It can be denied that she has a beautiful voice.
12. You must see the manager tomorrow morning.
→→ You've to see the manager tomorrow morning.
13. There was never any answers when we rang.
→→ Every when/time we rang,There was never any answers
14. That's an insulting name to use for him.
→→ Don't call such an insulting name to call him.
15. John asked if it was the blue one or the green she wanted.
→→ "Which is the one you want,blue one or green"-John asked
16. She liked Paris very little and Rome less.
→→ She thought Rome is not as interesting as Paris
17. I can meet you if you arrive before eleven.
→→ So long as you arrive before eleven.I can meet you
18. I've warned you not to go near that dog.
→→ I've warned you about going near that dog.
19. Why don't asked her yourself ?
→→ I suggest asking her yourself ?