A：What can I do for you?
B：I'd like a (pair) of shoes.
A：(Which colour) do you like?
B：Red.
A：What about this pair?They are very nice.
B：OK.( How much )are they?
A：20 dollars.
B：That's (right) .I'll ( buy ) them.
A：( here) you are.
B：Thank you!
A：You're welcome!