18. A. Yes, of course. Help yourself.
Help yourself: cứ tự nhiên
19. A. It's nice of you to say so.
hair style: kiểu tóc
20. B. Poor Ted!
knock sb down (phrasal verb with knock verb): to hit someone with a vehicle and injure or kill them
19. C. That's a good idea: Đó là một ý kiến hay.
20. A. Yes, give me some.
19. B. Many thanks
20. B. That's a good idea.
19. C. That's a very good idea. Let's do that.
20. B. Good luck: chúc bạn may mắn.
17. A. Thanks. It's nice of you to say so.
18. D. No, you needn't
17. B. It's our pleasure: Đó là niềm vui của chúng tôi..
18. C. Thanks, bye.
19. Pleased to meet you: Hân hạnh được gặp bạn.
20. C. Not at all
19. B. Yes, lets!
20. You can say that again = I agree with you.
19. A. Oh, thank you.
luggage (n): hành lí
20. C. Sorry, the seat is taken.

18. A
19. A
20. B
19. C
20. A
19. B
20. B
19. C
20. B
17. A
18. D
17. B
18. C
19. D
20. C
19. B
20. A
19. A
20. C.