No,they aren't.
这是用语以be 动词are提问的一般疑问句或者反意疑问句的否定答语。
Are they students?No,they aren't.
Are they playing football?No,they aren't.
Are these cars made in Japan?No,they aren't.
They are in the room,aren't they?No,they aren't.
They aren't singing,are they?No,they aren't.