一、以形式主语it引导的句型。
句型1. It happened(chanced) that clause. = sb. happened /chanced sth. = sb. did sth. by chance. 如：
It happened that he was out when I got there. 当我到那儿时，碰巧他不在。
句型2、It seems that sb. do/ be doing/ have done/ had done= Sb. seems to do/ be doing/ have done/ had done 如：(还有动词appear可这样使用)
It seemed that he had been to Beijing before.好象你以去过北京。
二、定语从句：
句型1、由as引导的非限定性的定语从句。如：
As we have known, he is a most good student.众所周知，他是个很好的学生。
句型2、由which引导的非限定性的定语从句。如：
He is a professor, which I have been looking forward to becoming.
他是个教授，那是我一直盼望的职业。(因为先行词professor是表示职业的名词，因此引导词用which，而不用who。(注意：关于which和as之间的比较请看语法的定语从句部分。)
三、让步状语从句
句型1、No matter what / which / who / where / when /
whose 从句， 主句。注意从句中的时态一般情况用一般现在时态。如：
No matter what you do, you must do it well.
四、条件状语从句
句型1、When / So long as / As long as / Once 从句， 主句。(从句也可以放在主句之后。)如：
As long as you give me some money, I will let you go.只要你给我一些钱，我就让你走。
句型2、主句 on condition that 从句。如：
I will go with you on condition that you give me some money.我和你一起去的条件是你给我一些钱。
句型3、主句 unless 从句.(注意：由于unless本身是否定词，所引导的从句的谓语动词用肯定。)如：
I will go there tomorrow unless it rains.我明天去那儿除非下雨。
五、原因状语从句
句型1、主句 in case 从句。(in case表示以免)如：
I will take my raincoat in case it rains.我要把雨衣带上以免下雨。
句型2、主句 due to / because of / owning to / the fact that 从句。如：
He did not come to school because of the fact that he was
ill.由于他有病了，所以没有来上学。
六、时间状语从句
句型1、When / While / As 从句， 主句。(关于它们之间的区别请看语法。)如：
When I was in the country, I used to carry some water for you.当我在农村时，我常常给你打水。
句型2、主句 after / before 从句. 如：
They hadn’t been married four months before they were
devoiced.他们绘结婚不到四个月就离婚了。
We went home after we had finished the work.我们做完此工作就回家了。
七地点状语从句
句型1、Where 从句， 主句. 如：
Where there is no rain, farming is difficult or impossible.哪里没有雨水，种庄稼是很难的或者是不可能的。
句型2、Anywhere / wherever 从句， 主句. 如：
Anywhere I go, my wife goes too.无论我去哪儿，我的妻子也去哪儿。
八、目的状语从句
句型1、主句 in order that / so that 从句.如：www.yingyuzuowen.cn
I got up early in order that I could catch the first bus.我起得很早，以便能赶上早班车。
九、结果状语从句
句型1、主句 so that 从句. 如：
It was very cold, so that the river froze.天气很冷，因此河水结冰了。
句型2、So 形容词/ 副词 特定动词 主语 … that 从句.
So interesting is this book that I would like to read it again.这本书那么有趣，我想再读一遍。
十、比较状语从句
句型1、The 形容词比较级……，(主句)the 形容词比较级 ……如：
The sooner you do it, the better it will be.越早越好。
句型2、主语 谓语 as 形容词原级 as 被比较的对象. 如：
He is as busy as a bee.他非常忙。
