learnfrom

learn by 是通过……方式，以……方式，用……方法，是以什么方式或方法

通常语法是learn by doing sth,

还有就是learn...by oneself(自学)

earn from是从……得知，向……学习，是指从某个地方或者人学到知识

通常语法是learn from sb向某人学习

短语

learn French from him 向他学习法语

learn English from me 向我学英语

learn lessons from mistakes 从错误中吸取教训

learn off 记牢，背熟