in,on,ai,for这四个词的用法

首先说明：是at不是ai

介词的时间用法：

时间点用 at - at 5 o'clock, at noon

时间段用 in - in 1997, in the afternoon, in the weekend

但若是星期几之前用 on - on Monday, on Friday, on Saturday evening

介词的空间用法：

准确的地点用 at - at the front desk, at my desk, at the entrance

在里面用 in - in his office, in the conference room, in the taxi

在上面用 on - on the bus, on the train, on the 8th floor （on 的概念是在上面可以走来走去的）

for的用法最多（详细）：

1. 表示“当作、作为”。如

I like some bread and milk for breakfast. 我喜欢把面包和牛奶作为早餐。

What will we have for supper 我们晚餐吃什么

2. 表示理由或原因,意为“因为、由于”。如

Thank you for helping me with my English. 谢谢你帮我学习英语。

Thank you for your last letter. 谢谢你上次的来信。

Thank you for teaching us so well. 感谢你如此尽心地教我们。

3. 表示动作的对象或接受者,意为“给……”、“对…… (而言)”。如

Let me pick it up for you. 让我为你捡起来。

Watching TV too much is bad for your health. 看电视太多有害于你的健康。

4. 表示时间、距离,意为“计、达”。如

I usually do the running for an hour in the morning. 我早晨通常跑步一小时。

We will stay there for two days. 我们将在那里逗留两天。

5. 表示去向、目的,意为“向、往、取、买”等。如

Let’s go for a walk. 我们出去散步吧。

I came here for my schoolbag.我来这儿取书包。

I paid twenty yuan for the dictionary. 我花了20元买这本词典。

6. 表示所属关系或用途,意为“为、适于……的”。如

It’s time for school. 到上学的时间了。

Here is a letter for you. 这儿有你的一封信。

7. 表示“支持、赞成”。如

Are you for this plan or against it 你是支持还是反对这个计划

8. 用于一些固定搭配中。如

Who are you waiting for 你在等谁

For example, Mr Green is a kind teacher. 比如,格林先生是一位心地善良的老师。

英语介词简介
表示时间的介词
表示场所和方向的介词
其他介词
表示时间的介词
表示“时间”的介词如下：
表示年、月、日时刻等用at，in，on
表示时间的前后用before，after
表示期限等用by，untill，till
表示期间等用for，during，through
表示时间的起点等用from，since
表示时间的经过等用in，within
表示年、月、日时刻等用at，in，on
at 用于表示时刻、时间的某一点
at noon
at night
at present
at 8 o'clock
We usually have lunch at 12.
on 用于某天，某天的上、下午（指具体某一天时，一律用on）         

on Monday
on Tuesday morning
on June 12th
on a cold night
on the night of May 1st
We didn't listen to the lecture on Friday afternoon.
in 用于表示周、月、季节、年，泛指的上午、下午、晚上
in the week
in May
in spring
in 1992
in the morning
in the afternoon                               
in the night
People go skating in winter.
表示时间的前后用before，after                        
before 在...之前
Wash your hands before dinner.
He will call me before he leaves here.
after 在...之后
Let's sing some songs after school.
Please close the door after you leave the room.
表示期限等用by，untill，till
by 在...之前;截至...
How many English books had you read by the end of last year.
untill(till) 直到...为止  (untill 与 till 可通用)
We didn't begin to watch TV untill (till) nine o'clock.
I'll wait for him untill he comes here.
表示期间等用for，during，through
for 达...之久                                                   

He has lived here for 20 years.
We will stay in the city for two days.
during 在...期间
They are going to have a good rest during the summer holidays.
through 一直...(从开始到结束)
They played the cards through the night.
表示时间的起点等用from，since
from 从...起(时间)
The meeting will be held from eight to ten.
The meeting will be held at eight
since 自从...以来(表示从以前某时一直到现在仍在继续)
I have been sick since yesterday.
The doctor has saved a lot of lives since he became a doctor.
表示时间的经过等用in，within                        

in 在...后(未来时间)
in an hour
in a week or so
He will be back in five hours.
They said they would arrive here in a week.
within 不超过...的范围
within 3 hours
I must finish painting the cat within five minutes.
They worked hard. They finished the work within 2 days at last.
表示场所、方向的介词
表示场所的介词: at,in,on,under,by,near,between.
表示方向的介词: into,out of,along,acros,through,to,from.  
at,in
at 在某地点(表示比较狭窄的场所)                        
at school
at home
at No.2 Baker Street
at a factory
I'll meet him at the Beijing railway station.
in 在某地(表示比较宽敞的场所)
in Beijing
in China
in the world
in the street
She was born in China.
on,under,over,above,below
on  a.在...上面,有接触面
on the desk
There are two maps on the wall.
     b.在...靠近...的地方
on the right
on the river
above 在...上方
Our plane flew above the clouds.
over 在...正上方,是under的反义词                       

There is light over Li Ming.
A few birds were flying over the sea.
under 在...下面;在...之内
under the table
under the jacket
The dog is under the table.
below 在...下方(不一定是正下方)
There are a lot of fishes below the surface of the water.
near,by
near 近的,不远的
near = not far
Is there a bus stop near here?
by 在...旁边,距离比near要近
by the window
by me
The boy is standing by the window.
between,among,around                             

between 在两者之间
My teacher is sitting between Tom and Mike.
What's the difference between A and B?
among 在三者或更多的之中
There is a beautiful house among the trees.
He is very popular among the students.
around 环绕,在...周围,在...四周
We sat around the table.
They walked around the street.
in front of,behind
in front of 在...的前面;在...的前部
The is a tree in front of the house.
There is a big desk for the teacher in front of the classroom.
behind 在...后面 是 in front of的反义词                  
There is a tree behind the house.
in,into,out of
in 在...之内,用于表示静止的位置
The students are in the classroom.
into 进入
The students run into the classroom.
He jumped into the water.
out of  和into一样,也表示有一定的运动方向
The students rushed out of the room.
along,across,through
along 沿着
I was walking along the river when it began to rain.
across 横过                                                            

I often swim across the river
through 贯穿,通过
The river was through the city.
to,for,from
to 到达...地点(目的地)或方向
He came to Japan in 1980.
Tom has gone to school.
for 表示目的地,"向..."
I'll leave for America next week.
leave for 动身去...
start for 出发去...
from 从...地点起...
It's about ten minutes' walk from here to the cinema.
How far is it from our school to the hospital?
其他介词
表示手段和材料的介词用with,in,by
with a. 和...在一起
Will you please go with me?
      b. 具有、带有
He was a handsome boy with large bright eyes.
      c. 用某工具或方法                                        
Li Li cut her hand with a knife.
I see with my eyes.
He wrote the letter with a new pen.
in 表示用什么材料(例如用墨水、铅笔)等，或用什么语言，或者表示衣着、声调特点时，不用with，而用in
She wrote a letter in black ink.
Don't write it in pencil but in ink.
by 通过...方法、手段
He goes to school by bicycle.
of, from
of (属于)...的;表示...的数量或者种类
This is a map of China.
Will you please give me a cup of tea?
from 来自(某地、某人);以...起始(时间或地点)              返回
I'm from Nanjing.
I have got a letter from my friend.
without,like,as
without 没有,是with的反义词
Men can't live without air and water.
I can't read the book without using a dictionary.
Please give me a cup of coffee without milk.
Please give me a cup of coffer with milk.
like 象...一样
Nancy is just like her mother.
as 作为
He is famous as a scientist here.
against,about                                                返回
against 反对;靠着
He is against the plan.
The teacher is standing against the blackboard.
about a. 关于;各处;身旁
Tell me something about your life.
He looked about himself.
I have no money about(= with) me.
       b. 询问某人某物的情况或提出建议
What about your sister?
How about going to the park?