句子按目的可以分为四类：陈述句、疑问句、感叹句和祈使句。

种类	用法	举例
陈述句	陈述一个事实或说话人看法	She may be late for class.
疑问句	提出疑问	What shall I do next?
感叹句	说话时的惊异、喜悦、气愤等情感	How fine it is today!
祈使句	请求、命令、叮嘱、号召等	Be careful, please!

在今天这讲中，我们先学习陈述句。

陈述句：分为肯定句和否定句（全否定和半否定）

肯定句：基本结构为主+谓
例如：It is cold in winter.
He went to London to pass his holiday.

否定句：
1、全否定：用not, no, never, neither, none, nothing等否定。表示“完全不是，完全不”的意思。
例如：He is not a worker.
Nothing is wrong with me.

2、半否定句：在句子里用否定词hardly, scarcely, little, few, seldom, rarely等。
例如：I hardly see anything in the room.
=I can see little in the room.

“all/both/every/each/+谓语+not”表示概念为“有的是，有的不是”
例如：All of them are not students.
=Some of them are students, some are not.

3、宾语从句的否定形式：用在think, believe, suppose引导的宾语从句里则否定主句。
例如：I don´t think he´ll come.
=He will not come in fact, I think.