13. met
14. not to eat
15. were
16. have walked
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17. resting
18. hurriedly
19. relaxing
20. unpolluted
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33. Như bạn làm
34. I wish I could go to Vung Tau Beach this weekend.
35. Mother said that Lan had to finish her homework before 5 o'clock.
36. He said that the Earth revolved around the Sun.