英语从句有很多种，主要包含有：主语从句、宾语从句、表语从句、同位语从句、定语从句、状语从句（地点状语从句、时间状语从句、结果和目的状语从句、结果状语从句、条件和让步状语从句等）。 第一，主语从句要注意区别这三种用法：

A.当从句过长时，谓语又较短，可将从句放在句末，由it做形式主语，常见的it引导的句型有：*It is a fact\a pity\a question\good news that… Eg:It has been more than three years since I saw you last time .

B.what引导的主语从句一般不用it作形式主语，表示“…的东西时”。 Eg:What we love to eat is sweet.

C.由what,who,when,why,whether等词引导的主语从句，都用陈述语序。 Eg:who will give us a talk is unknown at all…

第二，宾语从句常可连词that省略。固定搭配是in that(因为),except that(除了),but that(只是），其他介词后一般不接that引导的宾语从句。 Eg:I promised that my father would change his mind .

第三，表语从句出现在结构为“主语+系动词+表语从句”的句子中。 Eg:May the most intereting game to play is that there is no one can do it.

第四，宾语从句后如有宾补，要用形式宾语it来代替，而把宾语从句移至宾补之后。 Eg:She has made her face clear that she looked beautiful.

第五，同位语从句一般用连词that引导，用于对前面出现的名词作进一步说明。 Eg：She finally made the decision that she would join the fashion show.

第六，定语从句常用的关系代词有有who,whom,whose,which,that等，所修饰的先行词可以是名词或代词，也可以是一个句子。 Eg:Whom we must study for is a question of great importance.

第七，状语从句是用来修饰谓语动词、其它动词、定语、状语或整个句子的从句.

Eg:

Where you should go can be a hard decision to make in vacation planning.（地点状语从句） The camera is so expensive that I can’t afford it. 这个相机太贵了所以我无法买（结果状语从句） I got up early so that I could catch the first bus. 我很早期所以我可以赶上第一班巴士（目的状语从句）