一.定语从句篇
1.先行词与关系词被分隔。这种结构主要有三类：
（1）先行词+其他定语+定语从句
eg: Changes in the economy that lead to fewer job opportunities for youth make gainful emploument increasingly diff
iculty to obtain.
（2）先行词+状语+定语从句
eg: There exists no language or dialect in the world that cannot convey complex ideas.
（3）先行词+谓语部分+定语从句
eg: It can be predicted that questions will arise which will specific scientific answers.
2.when/where/why引导状语从句和定语从句的区分
秘诀：如果一个定语从句不是缺主语或宾语，而是缺状语，并且先行词是除了时间名词（这种情况下会when）和原因名词（这种情况下用why）以外的任何其他名词，就用where 引导定语从句。
eg: He told us how he dealt with the self-interest of countries to bring them into a kind of international accord where everyone seemed to benefit.(where相当于from which)
二.状语从句篇
1.本质：状语从句就是用连词将几个分句连接起来，以表达分句之间特定的逻辑关系。
2.while和when的区分
While=during that time（在…期间），表示某一时间段内发生的动作。因此从句谓语动词通常是延续性动词。When=at that time（在…时刻），从句谓语动词常是短暂动词；when从句也可用延续性动词。但往往是过去进行时态。While除表时间外，还有另外三种意思：表条件“只要”，表对比“然而”，表让步“尽管”。
2.引导条件状语从句的几个连词：if,unless,suppose,supposing,providing,provided,on condition that,so long as,as long as.
eg:You can arrive in Beijing earlier for the meeting provided you don`t mind taking the night train.
3.表示倍数比较的三种句型
（1）倍数+比较级：A is three times bigger than B.
（2）倍数+as…as：A is three times as big as B.
（3）倍数+名词：A is three times the size of B.
三.As专题
1.as用在名词后作后置定语
eg:Ambition as a healthy impulse（雄心壮志作为一种健康的冲动）
2.as用作副词
在as…as结构中，前一个as是副词，其后常接形容词或副词；后一个as是连词，可以省去。eg:This book is difficult.That one is as difficult.
3.as引导时间从句，译成“随着…”，或“一边…一边”。
eg:As the internet becomes more and more commercialized,it is in the interest of business to universalize access.
4.as 用于否定结构
（1）as前面的句子是否定，as句子本身是肯定。此时as译作“不像…”。
eg: Pure iron cannot be hardened by heating and cooling,as can steel,because iron lacks the necessary carbon.（纯铁是无法通过反复受热和遇冷来硬化，这点不像刚，因为铁缺少碳元素）
（2）as前面的句子是肯定，as句子本身是否定。此时as译作“但，然而”。
eg: He could love the child as he did not love Charles.（他可以爱上这个孩子，然而他却不爱查尔斯）
5.常见的as固定搭配
as well(也),as a whole(作为一个整体),as yet(迄今，到目前为止)。
四.Than专题
1.more than不仅仅是，不只是
eg: Teachers do much more than impartknowledge.They are forces in young lives.(老师不只是受业解惑，他们还是年轻生命的力量的源泉)
2.more than +形容词，表示“非常”。
eg: I would be more than readyto help you.(我将十分愿意帮助你)
3.more than+数字，表示“多于…”反义词是less than. eg: more than 25%(超过25%)
4.no more than=not any more than，表示“仅仅，只是”。反义词no less than，表“不少于”。
eg: He received no more than six months of formal education.=He didn`t receive any more than six months of formal education.
5.nothing more than,表示“只不过是”,相当于nothing but。反义词nothing less than,表示“不亚于，相当的”。
eg: There are always concerns that traditional dances performal in a theater are nothing more than a spectacle.(人们总是担心，传统的舞蹈仅仅是很壮观而已)
一点总结：nothing more than后面通常接名词，与nothing相呼应；no more than后面接数字。
6.than引导定语从句
eg; The project requires more labor than has been put in.(此工程需投入更多的劳动力)
分析：去掉more…than,例句就变为The project requires labor that has been put in. that 取代than作从句的主语。由于than须与比较级形容词more呼应，故than不能用that替换。
五.虚拟语气
1.虚拟条件句中，主句和if从句中的谓语动词形式如下：
表示虚拟的时间 If从句谓语形式 主句谓语形式
现在 过去式 would(should,might,could)+do
过去 过去完成式 would(should,might,could)+have done(been)
将来 were to(should)+do would(should,might,could)+do
2.倒装虚拟句
当if条件句中有助动词should,had或were时，可以省去if,而将should,had或were置于句首，从而构成倒装虚拟句，意义不变。
eg: It can`t tell you able an underprivileged youngster might have been had he grown up under more favorable circumstances.
3.跳层虚拟句
这类句子一般分为两部分，在语气上截然相反，一部分虚拟，另一部分不虚拟。两部分之间往往用but、or、otherwise连接。
（1）虚拟句+but+陈述句
该句型使用规律为：
a. 主语+would do,but+主语+一般现在时谓语形式；
b. 主语+would have done,but +主语+一般过去时谓语形式。
当然，句中的would根据情况可换成should、might或could。
eg: I would have gone to visit him ,but I was fully occupied the whole of last week.
（2）陈述句+or(or else,otherwise)+虚拟句
规律如下：
a. 主语+一般现在时谓语形式，or+主语+would do；
b. 主语+一般过去时谓语形式，or+主语+would have done
eg: We didn`t know his telephone number,otherwise we would have telephoned him.
六.动名词的复合结构
构成样式：my doing/Tom`s doing，这种结构常用在句中作主语或宾语。
物主代词（his,my,your等）或所有格名词（Mary`s,Tom`s等）于动词连用，即构成动名词的复合结构，用来引出动名词的逻辑主语，。当句子主语并不是动名词动作的执行者时，我们就需要给出动名词自己的动作发出者。
eg:
普通动名词 动名词复合结构
Jim insisted on reading the letter.(Jim坚持要看信) Jim insisted on my reading the letter.( Jim坚持要我看信)
He disliked working late.(他不喜欢工作到很晚) He disliked his wife`s working late(他不喜欢他老婆工作到很晚)