## 否定句
### 功能
说不
### 构成
在be动词后面加上not,否定句的核心就是not.
```
is not
am not
are not
```
### 例句
is am are 的选择是根据主语来的.
```
This is my name.
This is not my name.
```
```
i am not teacher.
```
```
they are not my books.
```
### 缩略形式
在口语中使用的是最多的. 读音也会发生变化. 有的音被去掉了或者改变读音. 在书面中也可以缩写,除非是非常正式的文件.
```
is not = isn't //t的读音经常被省略
```
```
am not = 'm not
```
```
are not = aren't
```