learn ,learn from ,learn about ,learn of的区别

learn 一般指学习某种语言的比较多,比如learn English

learn from 意思是听到获悉

I am sorry to learn of his illness.

听到他病了,我很难过.

learn from 意思是向…学习

It's necessary for us to learn from each other.

我们之间互相学习是必要的.

learn about 是学习某方面的知识