A ture friend is someone with whom we can share our life .其中的"with whom "做什么成分呢?!
A ture friend 主語
is someone 系表結構,做復合謂語
with whom we can share our life .定語從句
A ture friend is someone with whom we can share our life.=A ture friend is someone whom we can share our life with.=A ture friend is someone.we can share our life with him.with 引導的從句不是賓語從句嗎？with 是介詞，不能引導的賓語從句。whom是關系代詞，引導定語從句，whom在定語從句中做介詞with的賓語，因為whom做介詞with的賓語，此句把介詞with放在了關系代詞whom的前面。