1.It's amazing how little we can know about the people we love, your father, for instance.
一级结构:这是一个含有主语从句的复合句。主句是It's amazing,主句中的it是形式主语。主语从句是how little we can know about the people we love, your father, for instance,引导词是关系代词how little,little在这里是做名词用,这个主语从句做真是主语。
二级结构: how little we can know about the people we love, your father, for instance这个主语从句中含有一个定语从句we love,它修饰前面的先行词people,先行词在定语从句中做宾语,关系代词可以省略。句中your father是做people的同位语,for instance是做插入语。
2.Dig a little deeper.
A little在这句话中是做副词用,修饰副词的比较级,deep在这个句子中是做副词用。