Where are Roy and Rock?

W: Come in, please.
M: Hello,Roy. Where’ s Alan? I want her to type this letter for me.
W: I’ m afraid she can’ t, Rock. She isn’ t working today.
M: Oh,why? Is she ill?
W: No. She’ s preparing for an exam.
M: An exam? Is she going to school?
W: Yes, she is. She’ s learning Japanese in night school.
M: I see. Are you going to night school, too?
W: No, I’m not, not this year. But I’ m thinking about taking a course next year.
M: That’ s a good idea. Is it expensive?
W: No, not very. Anyway, it’ s worth it.