A: Linda, are you free this evening?
B: Not really! Why?
A: Some of our classmates are coming to my home for dinner.
B: I' m afraid not.
A: At about eight o' clock.
A: What about half past six?
B: Oh, I promised my brother I would help him with math at that time.
B: But I will come over to your house next time.
A: You're welcome.
A. Sure, I'd love to.