We are grateful to you that you have given us so much help.请

宾语从句!
that引导表示陈述句的宾语从句
宾语从句的引导词可以是1）动词,
He told us that they would help us through the whole work
2）介词,
We are talking about whether we admit students into our club
3）形容词,
I am sorry that I have troubled you so long.
所以是形容词grateful引导的宾语从句.
原因状语从句的引导词不用that,只有Since that,Seeing that,in that.

形容词后的宾语从句
比如i am sure that...

有一句话是这么说的我们可以经常看到： I am glad that you can come.
意思死很高兴你能来，我高兴的是你能来
同样这句话也是我很感激，感激的是你给过我如此多的帮助。
说明高兴，感激的内容，that 有这个用法
但具体是什么从句我还真说不清楚，是原因状语从句？怀疑！...