for:
(1) prep. （表示时间、距离）计，达
word that shows how far or how long
[例句]
I have waited for three hours.
我等了三小时。
They were silent for a while.
他们沉默了一会儿。
(2) prep. 开往，向
word that shows where someone or something is going
[例句]
She left Tianjin for Beijing.
他离开天津上北京去了。
(3) prep. 给，与，适于
word that shows who will get or have something
[例句]
This is a present for you.
这是给你的礼物。
(4) prep. 当作
as; as being
[例句]
I took him for his brother.
我把他当作是他的兄弟。
(5) prep. 因为，由于
by reason of, on account of; because of
[例句]
We could not see for the fog.
因为有雾，我们看不见。
They did not draw the conclusion for the following reason.
由于下述理由他们没有作出结论。
(6) prep. 就…而言
word that shows whom you are talking about
[例句]
It is dangerous for a small child to cross the road alone.
小孩子自己过马路危险。
He is tall for his age.
他小小年纪，个子倒挺高。（就他的年纪来说，他的个子算是高的。）
(7) prep. 为了，供
word that shows why you are doing something
[例句]
It is very cold for October.
十月里这样的天气真是很冷。
I have got some picture books for you to look at.
我有一些让你看的书。
No house was big enough for him to live in.
没有那么大的房子可供他住。
We work hard for socialism.
我们为社会主义努力工作。
(8) prep. （比赛或战斗时）代表，代，替
on the same side in a sport or fight
[例句]
They would run for the United States.
他们将代表美国去参加赛跑。
(9) prep. 价格，交换
word that shows how much something is
[例句]
I want to change this for that.
我想用这个换那个。
I paid two dollars for the book.
为这本书我付了两元钱。
(10) prep. 赞成，支持
word that shows you like an idea
[例句]
Some people were for the strike and others were against it.
有些人赞成罢工，另一些人反对。
(11) conj. 因为
because; on account of the fact that
[例句]
I am thirsty, for the sun is hot.
我由于天热而口渴。
of:
(1) prep. （表示所有，要占有）…的
word that shows what you have and own
[例句]
It's the custom of the country.
这是这个国家的习惯。
Beijing is the capital of China.
北京是中国的首都。
(2) prep. 从，在其中
out of,from among
[例句]
A cow is a kind of animal.
牛是动物的一种。
He is one of my best friends.
他是我的最好的朋友之一。
(3) prep. 包含有；有
containing,having
[例句]
Pass me a glass of milk.
递给我一杯牛奶。
He lives in a house of three rooms.
他住在一所有三个房间的房子里。
(4) prep. 由…制成
made from
[例句]
The bridge is made of stone.
这座桥是用石头造的。
(5) prep. 关于
about,concerning
[例句]
I have heard of the news.
我听说过这个消息。
It was he who told me the news of the victory.
是他告诉我这胜利的消息。
(6) prep. 叫做；系…
which is (called)
[例句]
The city of Harbin is a big city.
哈尔滨市是一个大城市。
(7) prep. 从；来自
from
[例句]
He is a man of humble origin.
他是一个出身微贱的人。
He was born of a good family.
他生于一个好家庭。
(8) prep. 表示地点
word that shows place
[例句]
He lives at the end of the road.
他住在马路的尽头。
(9) prep. 表示和别人的关系
word that shows what you are to another person
