Listen to a conversation between two students.
Man：Hey. Sally. How are you doing?
Woman：Well, okay. But I've got a bit of a problem.
Man：Oh, yeah? What's up?
Woman：Well, I forgot that tonight is the night my theater class is taking a trip to see a play. We're taking a bus into the city.
Man：Oh, sounds like fun.
Woman：Yeah. Well, we have to write a paper about the play for class. Cool thing is my professor got free tickets for us. He and the director of the play are friends. So the whole class is going for free.
Man：Free theater tickets. Excellent! Theater tickets can be expensive.
Woman：Yeah. Problem is, though, I have a big history test tomorrow morning and I really need to study. I've been putting it off and I kind of forgot that tonight was when the theater class would be going to the play.
Man：So you were planning to use tonight to study.
Woman：Yeah.
Man：Well, could you do your studying, you know, study for the history test when you get back from the play tonight?
Woman：Yeah. It would be late though. I could study some on the bus and stay up late when we get back from the play.
Man：Hmm...not exactly ideal study conditions though.
Woman：Exactly. So I was thinking I could go by myself into the city another night to see the play. The paper we have to write on the play isn't due for a couple of days. So they'd still be time.
Man：Then you can get a good night's sleep before the history test.
Woman：Yap. But I'd have to buy the theater ticket myself. It's only free if I go with the class tonight.