求这个英语句子的语法结构I stand here today humbled by the task before us

哪儿有状语从句啊.

humbled by the task before us：这是过去分词短语做伴随状语（如果把humbled看成形容词的话,就和后面形成三个排比的形容词短语）
grateful for..., mindful of ...,这是形容词短语做状语.其中you have bestowed 是定语从句,borne by our ancestors是过去分词短语做后置定语.

补充：
形容词（短语）作状语时, 通常说明主语的情况, 即表示主语的状态、性质、特征等.如：
The lost boy spent three days in the forest cold and hungry. 那个迷路的男孩又冷又饿地在森林中过了三天.
The moon had just
risen, very golden, over the hill. 月亮刚刚升起, 挂在山上, 十足的金黄色.

"humbled by... us"、"grateful ....bestowed"和“mindful....ancesstors"均为状语从句，“you have bestowed"和"borne by our an cestors"为定语从句。