定语从句作文80字【一】
1.从句为陈述句，常选择引导词that，that引导宾语从句无意义，不充当句子成分常省略。例句：He told us (that they would help us through the whole work.
2.从句为一般疑问句，常选择引导词if或whether，表示“是否”。在whether … or not结构中不能用if替换。例句：I don’t know if there will be a bus any more.
3.从句为特殊疑问句，常选择what,when,where,which,who,how等的疑问代词、副词作引导词。例句：He didn’t tell me when we should meet again.
定语从句作文80字【二】
“形容词短语”省略的理由和方式，与“分词短语”作后置定语一样。当它们不是句中的重点信息，就可以去掉关系代词和be动词。形容词作后置定语同定语从句一样，可以分为“限制性”和“非限制性”。
例1：I bought this comic book hot off the press. 我买了这本刚刚出版的漫画书。
例2：She is a kind lady, ready to help others. 她是一个善良的女人, 总是帮助别人。
例3：Companies large and small the world over have been developing their own “corporate universities”. 全世界大大小小的公司都一直在办自己的“公司大学”。
定语从句作文80字【三】
当which引导的定语从句指代主句全部内容时，可以把which改为it，作形式主语，把原来的主句改成正在主语。或者把定语从句的整个信息改换为名词短语作主语，使原来的定语从句变成简单句。
例4： He indulges himself all day in computer games, which makes his parents extremely sad.
改为：It makes his parents extremely sad that he indulges himself all day in computer games.
他整天沉湎于电脑游戏，这使他父母伤心至极。(主语从句
或者：His indulgence in computer games all day makes his parents extremely sad. (名词短语
定语从句作文80字【四】
一般说来，用on和at表示“as soon as, once”。on后面常接“来、去”之类的词，at后面常接“听到、看到”之类的词。in后面接其他带动作的词，相对于从属连词“while”。
例1：On removing them he was stunned to see that the plates were fogged where the crystals had covered them.当他把晶体揭开时，发现盘子上方雾蒙蒙，他吃了一惊。
例2：In running down the stairs, I heard the clock struck twelve.
我在跑下楼的时候，听见钟敲了十二下。
例3：He jumped with joy at hearing the news.他一听到这个消息就高兴得跳了起来。
定语从句作文80字【五】
基本概念定语：用于修饰名词或代词的成分就叫定语。 定语从句：如果修饰某个名词或代词的定语是一个完整的句子，这个句子就叫定语从句。定语从句所修饰的名词或代词叫先行词。定语从句放在先行词后面。定语从句的引导：定语从句的引导词代替的是先行词。
1、当定语从句所修饰的名词是事、物时，用that/which引导，且that/which在定语从句中作主语或宾语。e.g:a.Thisisthepenthat/whichIboughtyesterday.
2.当定语从句所修饰的名词是人时用that/who引导，引导词再从句中做主语或宾语。
3.定语从句修饰的\'名词时地点时用which/that或where引导:若地点名词在定语从句中是作主语或宾语就用that/which引导，是作地点状语则用where引导，可与“介词+which”互换。作visited的宾语作介词in的宾语作work的地点状语
4.当定语从句修饰的名词是时间名词时：若在定语从句中作主语或宾语用that/which,作时间状语则用when,同样可与“介词+which”互换。
5.当定语从句所修饰的名词在定语从句中表示原因时用why。’tcomeisstillamystery.
6.当定语从句修饰的名词和引导词后面的那个词之间是所有关系时，用whose引导。女儿已经出国的那个人是位医生
7.一些特殊情况：
定语从句作文80字【六】
如果定语从句的时态与主句的时态具有同时性(包括谓语有情态动词或之后性，则可以用“关系代词或关系副词+不定式”来简化，或直接用“不定式”来修饰先行词。要注意的是，此时的不定式一定要是及物动词，如果是不及物，则需要在动词后面加上相应的介词，使之成为及物动词短语。这个结尾的介词可以提前到关系代词前面，也可以继续留在句尾。前者是正式说法，后者是非正式说法。
例1：We moved to the country so that the children would have a garden in which they could play in.
我们搬到了乡下，好让孩子们有个花园在里面玩。
改为：We moved to the country so that the children would have a garden in which to play.
或者：We moved to the country so that the children would have a garden to play in.
例2：He felt miserable unless he had neighbors (whomhe could quarrel with.
他要是没有可以吵架的邻居就难受。
改为：He felt miserable unless he had neighbors with whom to quarrel.
或者：He felt miserable unless he had neighbors to quarrel with.
例3： The conference which will be held this afternoon is bound to be a great success. 计划在今天下午举行的会议一定会取得成功。
改为：The conference which to be held this afternoon is bound to be a great success.
或者：The conference to be held this afternoon is bound to be a great success.
例4：At a ceremony in Honolulu on Dec. 29, Postmaster General John E. Potter gave a preview of the Lunar New Year Commemorative Stamps Souvenir Sheet, the grand finale of the Lunar Year stamp series, which will be available in 2005.
12月29日，美国邮政总局局长约翰·E·波特在檀香山从句了农历新年的纪念邮票小型张的揭幕仪式，这枚小型张将于2005年正式发行，它为农历新年的系列纪念邮票写下了完美的结局。(注意：与定语从句一样，也可以采用非限制性形式
改为：At a ceremony in Honolulu on Dec. 29, Postmaster General John E. Potter gave a preview of the Lunar New Year Commemorative Stamps Souvenir Sheet, the grand finale of the Lunar Year stamp series, to be available in 2005.
