whom 代人,是who的宾格,常用作宾语从句的宾语,(有时可通用).例句：
I know whom you love.(我知道你爱的人是谁),可省略：I know you love.
比较who：I know who love you.(我知道爱上你的人是谁),不可省略.
whose代物,如：
Whose books are these?(这些书是谁的?)
Whose cell phone is this?(这手机是谁的?)