找出相对应的答句，将序号填入题前括号内。
--_________ Why are you laughing?
--We’re talking about the basketball game.
A. What’s the matter?
B. What’s the weather like?
C. What are you laughing?
--Sam, you shouldn’t ___the books down.
--I know. Sorry, Mum.
A. hold B. put C. take
Li Yuchun is my favourite singer. She sings very ___.
A. high B. well C. fast
--Xiaoyong looks very sad.Do you know ___ ?
--Maybe he misses his mum. She is in America.
A. whose B. why C. what