这句英语的结构是啥啊?

题目

这句英语的结构是啥啊?
If it had not been for your timely assistance in giving me first aid,I fear that the consequences might have been much serious.
it had not been for your timely assistance in giving me first aid这句话的语法结购是啥啊?能帮我分析下吗?

答案

“要不是你及时的采取急救措施来帮我,恐怕我的后果会很严重.”if引导的是虚拟条件句."If it ..not for..."（要不是.）在这个从句中.it为主语,had not been 为系动词be的过去完成式,for your timely assistance in gi...