Question

I think it important for us to do something 什么情况下is可以省略吗?

Answer 1

I think it important for us to do something

I think it is important for us to do something

都对,前者是it作为形式主语,是一句简单句

后者是 宾语从句,是复合句 I think （that）it is important for us to do something

省略了that