定语从句可用在作文【一】
“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”。
定语从句可用在作文【二】
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.
定语从句可用在作文【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
