从方框内选择正确选项，并把字母序号写在对话后面的横线上。（方框中有一个选项是多余的）

A. Sorry, but I am at work. B. Yes, are you free? C. My friend works at the theater and sometimes he gets free tickets. D. When is it? E. I can try. F. What is it about?

A: Hi, Helen. It's Robert speaking!

B: Hi, Robert. I can't talk too much with you.

A: I know, but I'm going to the theater. I've got two tickets for an opera. Would you like to go with me?

B: Thanks, I'd love to.

A: Tonight.

B: Tonight?

A:

B: I'm sorry, but I'm working late tonight.

A: Oh, can't you ask your manager for a leave?

B:

A: OK. Bye.