谁能帮我分析下这句子用了哪些语法?

i am amazed at是主句部分，后面都是介词at的宾语从句。从句中it是形式主语，for...to这个不定式复合结构是真正主语，must have taken 是谓语，how much courage 是宾语。宾语从句的结构和it takes two hours for me to finish the work是一样的。
对于一个成年人承受这样的耻辱和压力一定需要多么大的勇气，我感到吃惊。

宾语啊, i 主语 amazed 谓语 那后面的就是宾语了````

做修饰定语哦，这句话的主干是I‘m amazed at a grown man.其他的都是用来修饰这个grown man的。

I am amazed at how much courage it must have taken (for a grown man) to subject himself to such shame and stress.这句话应该这么断句：
i am amazed at /how much courage (it must have taken )for a grown man / to subject himself to such shame and stress
其中sb be amazed at 是amaze sb 的被动形式；it must have taken 是courage 的定语；to subject himself to such shame and stress是表目的,其中to such shame and stress 表一定的方向。for a grown man 在理解句子的时候可以暂时去掉，也可以放在句尾。
这句话也可以这么说 I am amazed at that much courage.The courage is taken by a grown man to subject himself to such shame and stress.