A: Hello, may I ask you a question?
你好，我能问你一个问题吗？

B: Yes. How can I assist you?
行。我能帮你点什么？

A: I want to buy a sweater.
我想买件毛衣。

B: What size?
什么尺寸？

A: I think a medium should fit me.
中号就行。

B: How about this one?
这件如何？

A: The color's nice. Do you have a dressing room?
颜色很漂亮。这儿有试衣间吗？

B: There's a fitting room right over there.
右边的那个地方有试衣间。