在定语从句中巧用“还原法”
来源：高中英语教学交流
发布时间：2011-12-28 10:16:00
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内容提要：但许多高一学生在定语从句的掌握和运用方面存在困难，做题时感觉云里雾里，采用“还原法”能帮助理清思路。
定语从句是英语基础语法的一部分，同时也是高中阶段语法教学中的重要部分。但许多高一学生在定语从句的掌握和运用方面存在困难，做题时感觉云里雾里，采用“还原法”能帮助理清思路。
一、何为“还原法”
“还原法”是指将因语法需要而改变的句子恢复其原来的模式，以检验所做的答案正确与否。
二、“还原法”的运用
1.将先行词还原到定语从句中，确定其在句中所充当的成份，以选择正确的关系词
例1 He has moved to the house____he was born.
A.which B.that C.when D.where
例2 He has moved to the house____is newly painted.
A.which B./ C.when D.where
这两个句子粗看似乎一样，但若分别把先行词house还原到定语从句中：第一句为“He was born in the house.”,house与介词一起做地点状语，应选择D;第二句定语从句还原为“The house is newly painted.”,先行词在句中作主语，关系代词不可省略，所以选择A.
再看下面两题：
例3 This is the reason____he asked us to carry out the plan.
A.because B.why C.which D.when
例4 This is the reason____he gave us for carrying out the plan.
A.because B.why C.which D.when
例3、例4的先行词都是the reason,但通过还原，我们知道前一句中the reason担当了定语从句的原因状语，即he asked us to carry out the plan for the reason,故应选B;后一句中the reason充当定语从句的宾语，即he gave us the reason for carrying out the plan,C为正确选项。
2.还原主句，理清主从句之间的关系，以免误入“陷阱”
例5 Alac asked the policeman____he worked to contact him whenever there was an accident.
A.with him B.who C.with whom D.whom
如果把he worked to contact him理解为定语从句，那就很难明白先行词the policeman与定语从句的关系。因此，我们应先还原主句：Alac asked the policeman to contact him whenever there was an accident,此时我们就能明白先行词the policeman与定语从句的关系是“he worked with the policeman”,所以根据句意应该选择C.
例6 I'll do everything____you.
A.I can to help B.I can help C.what I can to help D.that I can help
在选择时，学生很容易想到情态动词can后接动词原形，会选B或D.但用还原法来检测一下，就会发现主句应为：I'll do everything to help you,其中every thing是定语从句I can（do）的先行词，关系代词that省略，所以A才是正确答案。
3.把问句还原成陈述句，有助于正确理解句子
例7 Is this museum____we visited last year?
A.where B.the one C./ D.at which
例8 Is this the museum____we visited last year?
A.where B.the one C./ D.at which
把例7还原成陈述句This museum is____we visited last year,我们就可清楚地看到从句前缺少先行词和关系代词，因而应该选B（the one=the one that）。但如果把例8还原成陈述句This is the museum____we visited last year,我们会发现本句有先行词，只是缺少相应的关系代词，因此应选择C（句中省略了that或which）。
总之，利用还原法做题，可以帮助我们理解语法知识，提高答题的准确率。