There are some things that we understand,but about which animals know nothing.

问题描述:

There are some things that we understand,but about which animals know nothing.
这里的about是什么意思
前半句是:有一些我们知道的事.

关于、对于.
整句意思为:有些东西是我们所知道的,但关于那些,动物却一无所知