Excuse me , Miss .   Yes . May I help you ?   I'm a graduate student here in mathematics . I've just come from China and I've never used a western library before . I'll be here for five years , so I'd like to learn to use the library as efficiently as possible . I wonder if someone might have time to show me around .   I'd be very glad to show you around , but I'm very busy right now.Could you come back about 3,30 ? 