问题补充：
关于learn的用法learn的用法是learn to do sth,为什么书上还说learn how to do sth,不是应该为learn to how to do 英语
答案：
【答案】 字典上有.
vt.
1.学习;学会[+to-v][+v-ing][+wh-]
He has learnt a new skill.
他学会了一项新技能.
My brother is learning English now.
我的弟弟正在学英语.
2.认识到[Y][+(that)]
He has learned that dishonesty does not pay.
他已经认识到不诚实是没有好报的.
3.记住
The boy soon learned the poem by heart.
这男孩不久便能熟背这首诗了.
4.得知,获悉[+(that)][+wh-]
I learned from his letter that he was in Spain.
我从他的信中得知他正在西班牙.
We learnt the news this morning.
我们今天早晨得悉这一消息.
5.【幽】教训
vi.
1.学,学习[(+from)]
Why don you learn from my mistakes?
你为何不从我的错误中吸取教训呢?
2.得知,获悉[(+of/about)]
We learned of his marriage in the newspapers.
我们从报上获悉他结婚了.
learn to do没错
learn how to do sth 是个宾语从句,在learn加从句的情况下,就只能这样使用
