It was the first time that I had seen his film.这句话是定语从句还是强调句型?二者如何区分?the first time 在句中作什么成分?I had seen this film  为什么要用过去完成时?

问题描述:

It was the first time that I had seen his film.
这句话是定语从句还是强调句型?二者如何区分?
the first time 在句中作什么成分?

I had seen this film  为什么要用过去完成时?