听力原文：M: Hello, Julia. Why are you in such a hurry? W: Hello, Peter. I'm going to the theatre. They say there's a lecture on how to improve the skills of listening. Do you want to go with me? M: Oh, no. Thanks. I heard it yesterday. W: Really? What did you think of it? M: I liked it, but I was sorry to have missed the first part. W: Oh, what happened? M: I was held up on the way. So by the time I got there, the second part was just beginning. W: What a pity! But I'll tell you about it after I hear it. M: Thanks. I hope you'll enjoy it. Peter won't go with Julia because ______.