根据对话内容，在空白处填入恰当的表达。 A: Can I help you? B: Yes. I want to buy some tickets for the concert next week. A: 1 tickets do you want? B: Three. A: Which performance do you like, Thursday evening 2 Sunday evening? B: The day is not important, but my friends and I want to sit together. A: Let me see if I can help you. You know the singer is very popular and 3 sell well. B: I know. A: Ah, there 4 to be three such seats for Sunday's concert. B: That's fine. How much are they? A: 30 dollars each, 90 dollars in all. B: Here's 100 dollars. A: Thank you. 5 , your tickets and the change.