这些房间是汤姆和吉姆的.
翻译：These rooms are Tom’s and Jim's.
原文是“这些房间”,说明不止一间房间,也就是说是他们分别的房间,所以用：Tom’s and Jim's.如果用“Tom and Jim's”,则说明这间房间是他们共有的,译文应该是：
This is Tom and Jim's room.
问题补充：
These two rooms are Tom’s and Jim's.
正确答案是：C
见上.