补全对话
Li Lei: Oh, it's you, Lucy. 1 to see you.
Lucy: Nice to 2 you, too. Mary.
Li Lei: Come in, please, Mum, 3 is Lucy, my friend. She 4 American. And this is my mother, Lucy.
Mum: 5 do you do, Lucy?
Lucy: 6 do you do, Aunt?
Mum: Sit down, please, Lucy.
Li Lei: 7 you like 8 milk?
Mum: I don't like 9 very much.
Li Lei: 10 would you like?
Lucy: I'd 11 a pear.
Li Lei: OK. 12 you 13 ! What 14 something to drink?
Lucy: All right.
Li Lei: 15 it is!
Lucy: Thanks!
