解析：
learn v.学习，获悉，意识到
I learned a lot from my mother. 我从妈妈那里学到了很多东西。
We were very surprised to learn she had got married again. 我们听说她又结婚了，感到很惊讶。
I'm sure she'll learn from her mistakes. 我肯定她会从错误中吸取教训。
learn sth the hard way 历经挫折才懂得
解析：
dwelling n.住所，住宅
The doctor knows that his friend is an independent man and likes to have his own dwelling. 医生知道他的朋友是个独立的人，喜欢有自己的住处。
cave dwelling 窑洞
dwelling unit 住宅单元
,
