句子的分类:由句子结构来讲，可分为三类简单
一、简单句：由一个主语(或并列主语)和一个谓语（或并列谓语）构成的句子。
We cleaned the windows and tidied the room.
二、并列句：由并列连词and, but,so,or,for等把两个或两个以上的简单句连起来的句子。
1)I come from China and he comes from Japan.
2)Hurry up,or you'll miss the train.
3)He looked for it everywhere, but he couldn't find it.
4)She didn't know the answer to the question,so she asked the teacher.
5)He's interested in music while John is interested in sports.
三、复合句
宾语从句：宾语从句在复合句中作主句的宾语，引导宾语从句的关联词有that, if/whether, what, who, whose, which, why, when, where, how等。
句子的用途分为四种:
四、陈述句
（declarative sentence）：用来说明事实的句子。
China is the largest country in Asia. 中国是亚洲最大的国家。
I didn't tell him anything. 我什么也没有告诉他。
五、疑问句
( Question) , 即用来提出问题等的句子，不同的疑问句用不同的语调。
Are you a doctor or a teacher? 你是医生还是教师？
Which would you like, tea or coffee? 你想要哪样，是茶还是咖啡？
Is he sleeping, reading, or watching TV? 他是在睡觉，还是在看书，还是在看电视?
六、祈使句
通常以动词原形开头。
Take this seat.
Be careful.
否定结构: Don't move.
Don't be late.
七、感叹句
有多种表现形式，有时一个单词、短语或一个词组也可成为感叹句。
What a clever boy he is!
(他是个)多么聪明的男孩啊！
What an interesting story it is!
(这是个)多么有趣的故事啊！
根据语法功能，英语单词主要分为名词、动词、代词、形容词、副词、数词、冠词、介词、连词和感叹词十类。根据意义，又可将以上10类单词分为实词( Notional Words)和虚词(Form Words)。