，英语中的简单句就是只有一个主语和谓语，或者一个主语谓语家宾语的句子，例如I like english，我喜欢英语，复合句就是两个简单句的组合，例如I think english is very important，我认为英语是很重要的，I like music that has great lyrics，我喜欢有很好的歌词的音乐
复合句是两个或两个以上的简单句组成，每个简单句都有主谓，句子句子之间由连词连成；复合句分为并列复合句（也称并列句）和主从或从属复合句也称复杂句）。
如：What were you doing when your mother arrived home?
He said that he was late for school yesterday.
复杂句也称为从句、主从复合句，由一个主句和一个或一个以上的从句构成，用代词、副词、连词把一个简单句作为另外一个简单句的从属成分的句子；某个句子成分直接由从属分句表示，那么这种句子便不是简单句而是复杂句。
如：The students would have made better grades if they had studied hard.
