Question

I saw a man,on the head of whom stood a bird.我看见一个人,他的头上有一只鸟

Answer 1

1、I saw a man,on the head of （whom） stood a bird.

我看见一个人,他的头上有一只鸟.

whom指代的先行词是man,在（这人）的头上.

2、They arrived at a farm house,in front of （which） sat a small boy.

他们来到一处农舍,前边坐着一个小男孩.

which指代的先行词是house,在（农舍）的前面.