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11. He needn't to pay me.
12. He hadn't seen a dolphin before.
13. John and I asked for a drink because we were thirsty.
14. He drive carefully.
15. Unless you have her address, you can't write to her.
16. They left early in order to avoid getting caught in the traffic.
17. I wish I had good eyesight to get the job.
18. This flat is not big enough for three people.
19. Though I knew this place very well, I got lost.
20. I'll miss my train unless I leave now.