a. Lan: It's Mai's birthday, Mum. Is it OK if I stay the night at her house after the party?
b. Lan's mother: Certainly . Whose birthday is it?
c. Lan: OK, Mum. I'll be home before 10 p.m. then.
d. Lan's mother: Oh, I’m afraid not . You must come back home before 10 p.m. We're going to visit your grandparents early on Sunday morning.
e. Lan: Mum can I go to my friend's birthday party this Saturday evening?