$18.$ This is Mr. Carter whom I was telling you about. (Đây là ngài Carter, người mà tôi đã kể với bạn).

$19.$ Sandra who you were talking to, works in advertising. (Sandra, người mà bạn đang nói chuyện làm việc trong lĩnh vực quảng cáo).

$20.$ Susan is a girl who is good at learning foreign languages. (Susan là một cô gái, người mà giỏi trong việc học ngoại ngữ).

18. This is my Mr Carter. I was telling you about him. 

-> This is Me Carter about whom I was telling you.

19. Sandra works in advertising. You were talking to her.

-> Sandra, who you were talking to, works in advertising.

20. Susan's the girl. She is good at the learning foregin languages.

-> Susan is the girl who is good at learning foreign languages.