_____bedroom is very big.
A:Tom and Tony
B:Tom's and Tony's
C:Tom's and Tony
D:Tom and Tony's
从下列单词中选出不同类的一项( )
①新陈代谢 ②春夏秋冬四季更替 ③万有引力 ④彗星、地震预示国家衰败
⑤水往低处流 ⑥商品价格上下波动 ⑦遗传规律