Is your concert at 8:00?
No, it isn't.
Is your TV show at 7:30?
No, it isn't.
Is your party at 4:00?
Yes, it is.
Is your movie at 6:00?
Yes, it is.
Is your class at 11:00?
Yes, it is.
Is your appointment at 12:30?
No, it isn't.