请剖析：He was very kind to help us.
句中的不定式 to help us 是什么成分啊？结果状语还是缘由状语？还是其他什么状语？有哪些书上有剖析吗？
是缘由状语，而不是结果状语。与此类似的还有
I was somewhat surprised to see him.
We are sorry to hear of your father' death.
不定式在系表结构后，表产生这种状况是什么原因；而不定式作结果状语，多为出人预料的结果，如：
He tried to harm other people, only to ruin himself.
I arrived at the shop, to find I had left all my money at home.
手边任意一本系统的语法书，翻到非谓语的带to不定式，应该都有这部分内容。
