With是个介词，基本的意思是“用”，但它也可以协助构成一个极为多采多姿的句型，在句子中起两种作用;副词与形容词。

With是一个十分有用的介词，其用法也比较复杂，以下用法值得注意：
1. 表示方式、手段或工具等时(=以，用)，注意不要受汉语意思的影响而用错搭配，如“用英语”习惯上用in English，而不是with English。
2. 与某些抽象名词连用时，其作用相当于一个副词。3. 表示条件时，根据情况可与虚拟语气连用。如：
With more money I would be able to buy it. 要是钱多一点，我就买得起了。

with的用法

介词with的复合结构，常见形式及用法： 
1、with+现在分词 
They started working with the machine running. 
2、with+过去分词 
He is used to sleeping with the window closed. 
3、with+不定式（to do） 
With a lot of homework to do,Tom cann't go out to play. 
4、with+形容词 
She left the house with the windows open(开着的）/closed.（关着的）。这里的形容词有普通形容词，也有像closed，broken等过去分词演变的形容词。但只要明白语义，理解起来并不难。 
5、with+副词 
Don't leave the room with the lights on. 
6、with+名词（包括名词性短语）/代词 
The boy killed two birds with a stone his weapon. 
7、with+介词短语 
The teacher came into the classroom with a book in his hand.