A：
B：Yes, please. I want a sweater.
A：
B：Black.
A：Sorry, we don't have any black sweaters. Look at these sweaters. They are very nice.
B：
A：35 dollars.
B：OK, I'll take it.
A： .
B：Thank you.
A：.
A.What colour do you want?
B.Here you are.
C.Can I help you?
D.You're welcome.
E.How much is this one?
