句子按目的可以分为四类：陈述句、疑问句、感叹句和祈使句。

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, scarcely², 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.