口语中可以省略.
The doctor (whom) you
are looking for is in the room.
The person (whom) you just talked to is Mr. Li.
=The person to whom you just talked is Mr. Li. (介词后 whom不能省略)
The babies whom the
nurses are looking for are very healthy.
(固定短语中的介词一般不省略,介词仍放在动词之后)