A: ________ .
B: Not at all.
A.All right B.Here you are C.Thank you
A: ________ is David ?
B: He is in the classroom.
A.Where B.What C.Who
A:Is this your umbrella?
B:________
A.Perhaps this is your umbrella
B.Yes, this is your umbrella
C.No, it's his umbrella
A: Come here, Yang Ling.
B:________
A.All right B.Thank you C.Come in, please
A: Where's Yang Ling?
B:________
A.She's a student
B.She's at home
C.Yang Ling is my sister