Listen to a conversation between a student and her geology professor.

P: Mary, I am so glad that I ran into you.
S: Oh, hello, professor Jenson.
P: Listen, I know its short notice and maybe you have already made the plans for spring break, but one of my students just dropped out of the field trip to the Smithson river caves. You are next on the waiting list, so now there is room for you to come along.
S: You are kidding. I did not think there was a chance and well, it is a three day trip right? I agreed to spend next week helping professor Clark set up the new museum exhibition. I think she is really counting on me.
P: Yeah, three days. But you know, if you’d rather come on the field trip why not speak with her and see if she has any one to replace you.
S: Yeah, I’d hate to miss out on the caves. I'll definitely ask Professor Clark if there is someone else could help her.
P: You know we don't leave until Wednesday. If you still have to help out, any chance you could get the museum set up done before then.
S: Oh, yeah, not until Wednesday, so then, yeah, maybe that’s possible too.