为什么用from whom ,只用whom为什么不对

he is difficult from ___ he used to be.用what还是whom,who为什么 whom are you looking for 为什么是用 whom 为什么不用who do you know the girl with whom kate is talking 为什么连词要用whom 用 Jack (whom) I teach is lazy 这句中为什么用whom而不用who Where is the man that/whom I saw this morning?请问这句为什么用whom She is a lawyer whom I know?这里为什么用WHOM,请分析 i picked up a man whom i thought to be honest.中,为什么用whom? the man whom i saw told me to come back today.为什么用whom.不用who She had three sons,all of whom became doctors.这里面的连词为什么用whom 英语定语从句；为什么用whom不用who? To whom it may concern为什么要用it? 一道选择填空题：用whom还是who?为什么?