补全对话填写对话内容，使其完整、正确, 每空词数不限。

A: ?

B: Yes, please. I need two pairs of trousers.

A: OK. ?

B: Blue.

A: How about these two pairs?

B: Cool! ?

A: 11 dollars for one pair and 20 dollars for two pairs.

B: Great!

A: Here you are.

B: .

A: You're welcome.