根据问句，选择合适的答语。（10☆）
---Look! This is my red desk. ---__________ .
A. Great! It's very nice. B. Thank you. C. Nice to meet you.
How many ________do you have?
A.maths booksB.maths book C.a math s book
---Are the keys in the door ?---Yes, __________.
A. they aren'tB .it isn'tC. they are
--Is she in the bedroom? ---_______
A. Yes, it isn't. B. No, he's in the kitchen C. Yes, she is.