分析下这个英语句子的语法

问题描述:

分析下这个英语句子的语法
It is as if a single unimportant event set up a chain of reactions.

It主
is 谓
as if 引导后面从句
a single unimportant event set up a chain of reactions.从句
从句分析:a single unimportant event 主
set up 谓
a chain of reaction 宾