“It was his job to repair bicycles.”中的it是什么主语?

“It was his job to repair bicycles.”中的it是什么主语? 改错：it was his job repair bicycles It was his job to repair bicycles and at that time he used t it was his job to repair bicycles 这句话是强调强调句吗?如果不是 那时什么句子 It was his job to ripair bicycles.我不明白开始为什么用it was. his job is to repair bycicles 与 it is his job to repair byci 英语状语It was his job to repair bicycle and at that time he use 能这样表述吗?Frank's first job is to repair bicycles. Jack lost(丢失)his Job last week.It was difficult for him to f 短篇英译中Jack last his job last week.It was difficult for him to It is his nervousness that probably cost him his job这个是主语从句吗 he made it clear to the public___he would quit his job是什么从句