It's very helpful_____you_____(help) me.

It's very helpful_____you_____(help) me.
It's very helpful_____you_____(help) me.

It's very helpful_____you_____(help) me.
第一空of 第二空to help

It's very helpful_that_you_help_(help) me.
It形式的主语从句。你对我的帮助非常有用。

It's very helpful__of___you to help_____(help) me.
和It's very kind of you 跟to do 一样道理