定语从句省略1. 关系词充当从句的宾语的时候，可以直接省略，而从句不发生任何形式的改变。
This is the right book that you are looking for. = This is the right book you are looking for.2. 关系词充当从句的主语时，如果谓语结构为实词，将关系代词进行省略，而从句中的实词要发生形式的改变。
如果原本从句是一个主动语态，可以将动词直接变成ing形式。
如果原本谓语动词是一个被动语态，可以直接保留过去分词。
如Fruit that contains VC can relieve a cold.=Fruit containing VC can relievea cold.3.如果谓语结构为be+名词，这时，可以将be动词同时省略，将后面的名词和前面从句所修饰的名词构成同位语结构。
如I know Lucy who is the leader of the team.= I know Lucy, the leader of the team.4. 3.先行词为the way, 后面的关系代词可以是that, in which或者是不加任何关系代词。
如：I like the way you talk.5. 直接用于介词后作宾语的关系代词which不能换成that，直接用于介词后作宾语的关系代词whom不能换成who。
但若介词用于句末，则用作宾语的which, whom也可换成that, who6.（1）which用于下列情况：( I )如果引导的是非限定性定语从句; （II）关系代词充当介词的宾语，且介词位于关系代词之前;（III）先行词本身是that等。
（2）that用于下列情况：( I ) 先行词是all, everything, anything, nothing, little, much等不定代词；（II）先行词被all, any, every, no, little, much, some等词修饰；（III）先行词被序数词、形容词最高级修饰或先行词本身是序数词；（IV）先行词被the only, the very(正是、恰是),the last修饰；（V）先行词中既有人也有物；（VI）在which或who的特殊疑问句中含有定语从句等。
另外需要注意：先行词是the way，并在定语从句充当状语时，关系代词用that或省略，若用which,其前加介词in。
疑问：This was the house in which they lived last year.是否存在这种方式并正确——This was the house that they lived in last year.7.当关系词在从句中充当主语时，可以省略，后面的动词发生形式变化——主动语态时，动词变成-ING形式被动语态时，动词保留过去分词形式I know the girl who comes from BJ.I often like reading short novels which were written by Hemingway.I often like reading short novels written by Hemingway.I raise a dog which is named KING.* I raise a dog named KING.I believe the candidate who made the speech in the assembly yesterday is sure to win the support.*I believe the candidate making the speech in the assembly yesterday is sure to win the support.I know the boy who was praised by the teacher.The book which is related to the development has been published recently.They lived in a house facing the south.= They lived in a house which faced the south.The workers working in the factory are well-paid.= The workers who work in the factory are well-paid.= The workers who are working in the factory are well-paid.The tie worn by our head was made in Shanghai.= The tie which is worn by our head was made in Shanghai.The book written by Wang sells well.= The book which was written by Wang sells well.状语从句省略1. 主句和从句的主语保持一致，称为分词作状语；省略从句的主语，将后面的动词发生形式变化，主动语态变成ing形式，若是被动语态，则变为ed形式2. 如前后主语不一致，则称为独立主格结构。
省略方式：关系词（可保留）+动词形式变化（ing\-ed）。
Because mum was ill,I didn't go to school.----Mum being ill,I didn't go to school.When he finished his homework,we went out to play.—-He finishing his homework,we went out to play.一、时间状语从句中的省略When (she was) very young, she began to learn to play the piano. 她很小时，就开始学习弹钢琴。
While (I was) at college, I began to know him, a strange but able student. 我在上大学时就开始认识他，一个奇怪但有能力的学生。
When arriving, send me a telegram. (When you arrive, send me a telegram.) 到达之后，来个电报。
Before leaving, turn off all the lights. (Before you leave, turn off all the lights.) 走之前，请关闭所有的灯。
Don’t come in until (you are) asked to.不叫你请你不要进来。
Whenever (it is )possible, you should come and help. 不管什么时候只要有可能就来帮忙。
You should let us know the result as soon as(it is) possible. 你应尽快让我们知道结果。
注：as在引导时间状语从句时，没有这种省略现象。
我们不可说As walking, she found a nice shining thing on the ground.二、地点状语从句中的省略地点状语从句的省略常用下列结构：where(ver) possible, where(ver) necessary,Lay these books where possible you can find them easily. 把这些书放在你可能容易找到的地方。
Put in articles wherever necessary in the following passages. 在下列文章中需要的地方填入冠词。
三、条件状语从句中的省略常用的句型是：if necessary, if possible, if true, if anyone等。
如：Send the goods now if (they are) ready. 货物如果准备好了，请送过来。
He will come if (he is) asked. 如果叫他来，他就来。
If (it is) necessary, ring me at home. 如果有可能，朝我家里打电话。
Come along with me if (it is) possible. 如果有可能和我一起去吧.。
If (it is) true, this will casue us a lot of trouble. 如果是真的，这会给我们带来很多麻烦。
There are few people nowadays, if (there are) any, who remember him. 很少有人能记起他。
黑夜笼罩大地，谁也看不清远处黑压压的一片是什么东西。
There being no bus, we had to walk home.由于没有公共汽车，我们只好走回家。
2. 名词(代词)+过去分词The workers worked still harder, their living conditions greatly improved.由于工人们的生活条件大大提高，他们工作得更起劲了。
He was listening attentively in class, his eyes fixed on the blackboard.他上课专心听讲，眼睛紧盯着黑板。
3. 名词(代词)+不定式在“名词/代词+动词不定式”结构中，动词不定式和它前面的名词或代词如果存在着逻辑上的主谓关系，动词不定式则用主动的形式；如果是动宾关系，则用被动形式。
The four of us agreed on a division of labor, each to translate a quarter of the book.我们四人同意分工干，每人翻译全书的四分之一。
Many trees, flowers, and grass to be planted, our newly-built school will look even more beautiful.种上许多的树、花和草后，我们新建的学校看上去将更美。
4. 名词(代词)+形容词The Trojans asleep, the Greek soldiers crept out of the hollow wooden horse．特洛伊人睡着了，于是希腊士兵从中空的木马里悄悄爬了出来。