learn from study 通过钻研学习
Has he learned [learnt] (how) to skate? 他学会滑冰了吗?
One is [You are] never too old to learn. 【谚】 活到老学到老.
learn (off) by heart [rote)
You must learn to be more patient. 你必须学会更加忍耐.

I learnt it from [of] him that... 我从他那里听说…

learn to one's cost 学乖,汲取教训
You will learn (=come) to love it. 你慢慢会喜欢它的.
He learns very fast. 他学东西很快
I am [have] yet to learn. 我还不知道呢(通常含有不相信的意味).
I'll learn you. 【非标准说法】 我将教训教训你.