在下面对话的空白处填入适当的话语（话语可以是句子、短语或词）。

A: , Tina?

B: My birthday is on December 7th. You know, today is my birthday.

A: Oh. Happy birthday to you!

B: , Lucy.

A: I want to buy a gift (礼物) for you. Let's go to the store. OK?

B: Great! Thanks very much.

(In the store)

C: ?

A: Yes, please. I'm looking for a pair of socks for my friend.

C: What color does she like?
A: She likes black.

C: What do you think of these socks?

A: They're great. ?

C: 20 yuan.

A: OK, . Thank you.