Apples are ON the tree.
Birds are IN the tree.

a boy from the ghetto 来自贫民窟的男孩子
（Here, the preposition from tells us the relationship between ghetto and boy.）
a bone for the dog 一根给狗吃的骨头
（Here, the preposition for tells us the relationship between dog and bone.）
A preposition precedes a noun (or a pronoun) to show the noun's (or the pronoun's) relationship to another word in the sentence.
介词是用来表示名词（或代词）和句子中其他词之间的关系的一个虚词。

表时间时：
at for a PRECISE TIME
具体的时刻点
in for MONTHS, YEARS, CENTURIES and LONG PERIODS
月，年，世纪，长的时间段
on for DAYS and DATES
日期或者星期
The appointment is at 8:30 today.
会议在8:30。
The Qing Dynasty is in 1911.
清朝在1911年。
I will see you on the 15th of October.
我10月15号见你。

表地点时：
At a Point 在具体的地点
In tells us the noun is in an enclosed space (surround or closed off on all sides). Basically, when something is inside something. 在里面
On tells us that the following noun is located on a surface. Use on when one thing is attached to or touching something. 在上面，有接触面或者接触点
She's waiting at the entrance.
她在入口处等。
He's sitting on his chair at his desk.
他坐在桌子那里的凳子上。
I work at a bank.
我在一家银行上班。
Meet Simon at the end of the road.
在路的尽头去见Simon。
In a box 在盒子里
In a room 在一个房间里
In a country 在一个国家里
You left your glasses in the bathroom.
你把你的眼镜落在了浴室里。
On the table. 在桌子上
On the floor. 在地板上
On the chair. 在椅子上
Is that a spider on the wall?
墙上是一只蜘蛛吗？

其他：
About- A specific subject
关于
"What is that book about?"
那本书是关于什么？
By- Doing this
通过
The book was written by Jack Johnson.
这本书是 Jack Johnson 写的（出自他之手）
for 作用
What are chopsticks used for?
筷子是用来干嘛的？
Of- belonging or to belong - 所属关系
The Great Wall of China 中国的长城