什么是介词短语?(速求) 千万不要介词的解释！！

介词是一种用来表示词与词, 词与句之间的关系的词。介词和其他代词或名词搭配形成介腔尘词短语。

at (1)表示在小地方; (2)表示“在含桥……附近，旁边”
in (1)表示 在大地方; (2)表示“在…范围之内”。
on 表示毗邻，接壤
to 表示在……范围外，不强调是否接壤
He arrived at the station at ten.
He is sitting at the desk.
He arrived in Shanghai yesterday.
Jiangsu lies in the east of China.
Russia live on the north of China.
Fujian is to the south of Jiangsu Province.
2)above, over, on 在……上
above 指在……上方,不强调是否伍老禅垂直，与 below相对；
over指垂直的上方,与under相对,但over与物体有一定的空间，不直接接触。
on表示某物体上面并与之接触。
The bird is flying above my head.
There is a bridge over the river.
He put his watch on the desk.
3)below, under 在……下面
under表示在…正下方
below表示在……下，不一定在正下方
There is a cat under the table.
Please write your name below the line.

在房子后面，behind the house
on the table, under the tree, next to the shop.等。
这类由介词和宾升山语（一卜祥般是名词型笑搏）的词组，就是介词短语。

“介词+宾举坦语”构成 介词短正拍桐语
如贺巧at home .by plain ,for 3 years ,on the morning ,in the tree ,among the students等等

介词短语也成介词词组（adjective phrase） ，是以介词为中心词（head）的词组。它的结构一般是 （修饰语）+介词+不足成分+补足成分（又叫介悔告搭词宾语）
eg：1、碧拿友凳 Do you think you can borrow some money from your friend?(from your friend)
2、 That short story is based upon an incident in the author’s life.(in the author's life)
3、 Now their footsteps could be heard directly above my head.(directly above my head)