That you don't know how to do it doesn't bother me,but you told me you will.请问这里That是什么

That you don't know how to do it doesn't bother me,but you told me you will.请问这里That是什么

你看下这个句子就知道了.It doesn't bother me that you don't know how to do it .
that you don't know how to do it 是主语从句,上句中,我换成了IT作形式主语,就清楚了.That在名词性从句中只作连词,起连接作用,没有具体意思.

指代you don't know how to do it

这里的that是主语，you don't know how to do it 是定语从句，用来修饰that的。
doesn't是谓语，这句话的主要成分就是that doesn't bother me。