根据所给情景,完成下列对话,每空一词.
A:_____that?
B:that's sam.
A:_____You know him?
B:yes,he's my good friend.
A:Why______you like him?______looks so serious.
B:_____he's funny.He can talk like our teacher.
A:_____is he_____?
B:He's outgoing and friendly_____others.
A:But I don't like a boy_____so long hair.
B:It's not important.I think he's_____best student