介词宾语 meaning in Chinese

prepositional object

I am against your spending too much money on stamps
（作宾语? ?介词宾语）我反对你花很多钱买邮票。
This is the room ( that / which ) we ' ll celebrate the new year in
这是我们将要在里面庆贺新年的房间。（充当介词宾语，可省略。）
The mathematician always works in his study with the door locked
这数学家总是锁着门在书房工作。（这句是介词宾语的补足语。）
This is the room which / that will be used for the celebration of the new year
这是我们将要在里面庆贺新年的房间。（充当介词宾语，可省略。）