概述
介系词的用法就是放在名词的前面，与名词共同构成一个意义单元，称为介系词片语，当做修饰语使用。
可以当做形容词或者副词使用，是最有弹性、使用频率最高的一种修饰语。
The company is in trouble。 做名词
I leave for HongKong tommorrow. 做副词，修饰leave
The country is rich in mineral wealth. 做形容词，修饰rich
The new janitor works half-heartedly at best. 做副词，修饰副词half-heartedly
介系词与介副词
介副词，看起来和介系词一模一样，但是后面却没有受词，而是直接当做副词使用，修饰前面的动词。
例如：
Come in.
The soldier stood up.
介系词和介副词一起使用
The plumber went down to the basement.
down是一个介副词，to是介系词，to the basement构成介系词片语，当做地方副词使用，修饰went。
He has gone over to your house.
over为介副词，to为介系词
介系词与动词片语
试比较底下两个句子：
The man slept on the couch。 S+V句型，后面跟介系词片语
The man turned on the light。 S+V+O句型
对于句2，应该把turn on当做一个动词来看，后面的the light是其受词。
像turn on这种情况，后面加上介副词，构成一个意义单元的，应该当做一个动词来看待，成为片语动词。
片语动词的种类
及物动词、不可拆开(受词必须放在片语后面)
get over 康复、痊愈
look into 调查、了解
take after 类似、像
stand by 支援
不及物动词
come about 发生
How did this all come about?
fall off 下跌
Business has falled off badly since the SARS epidemic。
go off 爆炸
turn up 出现,出席
及物动词、可拆开(受词可以放在片语后面，也可以放在中间)
bring up 抚养长大
如果受词是代名词，一般放中间。
call off 取消
turn down 拒绝
I’m going to turn down his offer.
I’m going to turn his offer down.
I’m going to turn it down.
make up 捏造，编造
三个词以上的片语动词，及物，不可拆开
catch up with 赶上
drop out of 退出
get away with 侥幸逃脱
go back on 食言
空间介系词
点:at
The bus will stop at the dock to pick up passengers.
在巴士的行走路线上,码头是一个点。
The instructor points to the poster on the wall and says,”Never point your gun at anybody。”
如果是[指向某个方向]，应该用point to,这个介系词to相当于toward的用法，如果说[瞄准]，那是把目标当成一个顶点，就该说point at。
线:on,along
The student memorized 10 new words on his way to school。
There are many beautiful villas along the beach。
面:on
I strained my eyes but couldn’t see any ship on the sea。
There is a picture hanging on the wall。
体:in
I like to stay in my office because it’s quiet there。
对于怎样理解空间介系词，需要根据具体的句意来分析，在不同的场景，同样的受词，可能会用不同的介系词。
We’ll go our seperate ways,and meet at my office at three。
比喻用法
各种比喻，拟人的修辞手法。
That shameless man is beneath contempt。
What the lecturer is saying is quite beyond my comprehension。
时间介系词
at [定点]
in [比较长的一段时间]
on [哪一天,星期、日期、节日]
My birthday is on January 23。
其他介系词
apart from 除了…之外
We had no trouble on the way apart from a flat tire.
介系词做副词，表示让步
as for 至于
for 为了…
This document is for your information only。
of …的
可修饰名词，动词
These shoes are made of rubber。
Holland is part of Europe。
at 以…
The car was going at 90km per hour。
but 除了
No one but(except) a fool would accept a challenge like that。
in 以(表达方式)
He signed his name in black ink。
up to 由…决定
It’s not up to me to decide。
I’m not up to this job。
between/among
between有表示位置的功能，而among仅仅表示在其中
except/except for 除了…
on/about 关于…
He has written a book on the temples of the Upper Nile。
He’s talking about his childhood。
over 关于…
They are aruing over their share of the property。
through 经由…,靠
He achieved fame through sheer hard work。
介系词片语的位置
介系词片语是很有弹性的修饰语，可以当做形容词或副词使用。他在句中的位置，通常是放在他所修饰对象额寿面作为后位修饰语使用。
I love to read books with pictures in my lesisure time。
摆正位置，才不会造成句子的模棱两可。
