1、 after/ in 皆可表示时间在……之后，其区别为：
after 1）表示“在某点时间之后”，用于将来时。如：
We’ll go out for a walk after supper.
2）表示“一段时间之后”，用于过去时。如：
My mother came home after half an hour.
in表示“一段时间之后”，用于将来时。如：
We’ll go to school in two weeks.
2、at/in/on
at seven o’clock（具体某一时刻用at）
in April /in April,2002（具体某一月份或年份用in）
on April 5,2002/on the morning of Monday（具体某一天用on）
3、in /by /with
He writes in black ink.（用……材料）
The guard cut one boot open with a knife.（用……工具）
She always goes to school by bike.（用……手段）
4、between /among
Can you say the differences between the two words?（两者之间）
Premier Chou En-lai lives among the people for ever.（三者或三者以上）
5、besides /except
We have seen the crocodile besides Lifang.（除……之外，还有）全部计算在内
We are all Chinese except Tom in our class.（除……之外）不计算在内
6、on /over/ above
There is a boat on the desk（在某物面上，与此物接触。）
There is a bridge over the river.（在某物正上方，与此物不接触，或横在某物上，或覆盖在某物上。）
She spread a cloth over the table.
He held his heads above his head. （“在……上”，强调“高于。”）
7、on/ in / to
Mongolia is on the north of china.（与中国接壤，不属于中国）
Japan is to the east of china.（不属于中国，且不接壤）
Taiwan is in the east of China.（台湾属于中国）
8、since /for
since 表示从过去某一时间以来
for 表示一段时间
I have been living here since 1982.（自1982年以来，我一直住在这里）
I have been living here for 20 years.（我已经在这里住了20年了）
9、of /from
The desk is made of wood（看得出材料）
Paper is made from wood.（看不出材料）
The bread is made up of flour, sugar and milk.（由数种成分组成）
10、by /on
He used to go to school by bike.（抽象概括）
He came to school on this bike yesterday.（具体到哪一辆车）
11、of /for
It’s kind of you to come to see me.（既说明不定式本身特点，又说明逻辑主语的品性）
It’s important for you students to learn English well.（只说明不定式本身的特征）
12、of /in
This is the most interesting of all the stories.（从个体的集体着眼）
China has the largest population in the world.（从总体概括着眼）
13、of /about /on表示“谈及，论述”
Do you know of American singer John Denver?（涉及浅层关系）
I have never heard about him.（表示谈论等深一步的关系）
This book is on grammar.（以……为主要内容）
14、through /past/across
The new railway runs through the small town.（穿过）
He walked slowly past the tall building.（从旁边经过）
Mary walked across the park to do some shopping.（强调从一边到另一边）
15、by/ with通过……手段
We write with a pen.（表示较具体的事物）
There’s nothing to gain by waiting.（表示抽象）
16、despite = in spite of（介词） / although（连词）
despite 是介词，后面接名词或动名词，不能跟句子
although是连词，后面要跟句子。
Although I was ill yesterday, I still went to school.
Despite failure in the exam, I still have a chance to win in the term.
17、as /like
as 1）用作介词时意思为“作为……，充当”如：
She acted as an interpreter.
2）用作连词时意思为“像……一样；当，由于”
As it was cold, I didn’t go outside.
like 用作介词，意思为像……一样
John sings like a nightingale.
18、by day（指白天）/ by the day（按日计算）
I worked here by day and I am paid by the day.
worth 的用法
worth，worthy，worth-while都为adj. 意为"值得"。
1. worth： be worth + n. 当名词为金钱时，表示"…… 值得……"
be worth doing sth. "……某事值得被做"
The question is not worth discussing again and again.
2. worthy：be worthy of +n. 当名词为抽象名词时表示"……值得……"
be worthy to be done "某事值得被做"
The question is not worthy to be discussed againand again.
3. worth-while： be worth-while to do sth "值得做某事"
