if you had seen the room 这句话语法对吗

问题描述:

if you had seen the room 这句话语法对吗
错了,i want to know if you had seen the room

我觉着应该是:I want to know if you saw the room.
过去完成时(had done)应该用在过去的过去
即 I wanted to know if you had seen the room.