因为这里用到了because从属连词,这句话不再是非限制性定语从句,而是原因状从,状语从句也需要有自己独立主语some of them,所以不能用关系代词whom(就算是去掉because成为非限制性定从,也只能用which,因为先行词是arts是物)。 而第二句You may find many famous museumss there, the most famous of which is Louvre. 逗号后面没有并列连词从属连词等,就是非限制性定从,先行词为museums,所以用which关代