whom
US
UK whom pron: (objective of who) (宾格)
SC 谁 shuí
TC 誰
TC 誰
Whom did you see when you were there?
你在那里看到了谁？
from whom pron: formal, written ([sb] who is source of)
SC 自某人 zì mǒu rén
SC 从某人处 zì mǒu rén，cóng mǒu rén chù
Please return the book to the person from whom you borrowed it.
of whom pron: formal, written (amongst, out of: a group)
SC 谁的 shuí de
The lost hikers, some of whom were suffering from hypothermia, were rescued from the mountain earlier today.
The police have arrested four men, all of whom are from the Liverpool area.
To whom it may concern expr: formal, written (salutation in a letter) (信件)
SC 敬启者
TC 敬啟者
TC 敬啟者
SC 致有关人士，给有关人士(信件)
To whom it may concern, I am writing to express my dissatisfaction with my recent visit to your restaurant.
敬启者，我写信是为了表达我对最近去你们餐厅的不满。