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12. He did all his work and then he went home.
→ Before ____________________________________________________________________
13. She didn’t finish her exercises until yesterday.
→ It was not until ______________________________________________________________
14. It was not until all the seats were full that the play began.
→ The play ___________________________________________________________________
15. He will have left by the time you arrive.
→ When _____________________________________________________________________
16. I will return this book to you when I finish reading it.
→ As soon as _________________________________________________________________
17. Mark had written 5 best sellers before he was 20.
→ By the age__________________________________________________________________
18. During my dinner, the phone rang.
→ While _____________________________________________________________________
19. Hardly had Peter received the message, he hurried to the office to see what happeneD.
→ As soon as _________________________________________________________________
20. Do you have any experience of driving this kind of car?
→ Have _____________________________________________________________________