Why didn’ t the girl go to the movies?

M: Do you want to see a film tonight?
W: I can’t. I have to review my lessons.
M: Are you having a test tomorrow?
W: Yes. We’ re having our mid-term test.
M: I wish you good luck.
W: Thanks a lot. But I’ m a little nervous.
M: Nervous? You used to study very well.
W: But I haven’ t studied for a long time.