[非谓语动词和从句转换]状语从句与分词作状语的转换篇一: 状语从句与分词作状语的转换状语从句与分词作状语的转换时间、原因等状语从句可以转换成分词作状语，但这种转换是有条件的，也有一定的规律可循。
[]一、基本规则，也是最重要的规则是：从句的主语与主句的主语必须一致，变从句而主句不变。
如：They did not go to the Summer Palace because they had a lot of work to do．由于从句的主语与主句的主语都是they，可以把从句中because 和they去掉，把had变成having，即成现在分词短语作原因状语：Having a lot of work to do，they did not go to the Summer Palace．二、从句如果表示主动、完成，进行的动作，则转换成现在分词；如果表示被动，则转换成过去分词。
1．When he heard a cry for help，he rushed out．从句中，he was与heard是主动关系，表示“他听见”。
则可变成现在分词作时间状语。
Hearing a cry for help，he rushed out．2．The boy Cater went up to his teacher and said“sorry”because hewas great-ly touched by his words．从句中，he was touched是被动关系，是“孩子被深深地触动了”，则变成过去分词作原因状语。
Greatly touched by his teache r’s words，the boy laterwent up to him and said“sorry”．三、如果从句的主语与主句的主语不一致，该怎么办？请看下例：1．As the heroes’ deeds moved them deeply，they decided to study even harder．句中，主句的主语是they，而从句主语是the heroes’deeds，主语不一致，这时可以把从句变换一下句型，变成被动语态。
即成As they w ere deeplymoved by the heroes’deeds．从句的主语与主句的主语都是they，就可转换成：Deeply moved by the heroes’deeds，they decided to study even harder．下列的句子中主语也是不同的。
2．The professor came into the lab；a group of students followed him．这是两个简单句，如果中间加个and也可看成并列句。
但主语不同，可以先把第二句变成：He was followed by a group of students．全句就转换成：Followed by a group of students，the professor came into the lab．四、如果看不出有从句，该怎么办？请看下例：He recognized the man who had been his classmate ten years before，so he wentover to say hello to him．这句中，看不出有从句。
so是并列连词，表示“因此，于是”等意思。
这样一来，前面那一句就有表示原因的意味。
这一句可以改写为：Because he recognized the man who had been his classmate ten years before，he went over to say hello to him．变成一个原因状语从句，即可转换成现在分词作原因状语。
Recognizing the man?许多有and或没有and的并列句，只要主语一致，往往可能换成分词作伴随状语。
如：The students went home from school；they talked and laughed．可转换成：Talking and laughing，the students went home from school．五、如何判断要不要有一个Being？如：As he was very old，he had to give up his teaching．可转换成：Being very old，he had to give up his teaching．再看下例：As he was moved by the story，he decided to learn from the heroes．则转换成：Moved by the story，he decided to learn from the heroes．而不是Being moved?为什么呢？原来前面的那一句的was是系动词，后面跟的是表语。
又如：As he was an engineer，he knew exactly what to do．an engineer．是名词作表语，即可转换成：Being an engineer，he knew exactly what to do．而后面那一句的被动语态was是助动词，只需过去分词就可以了。
但英语中有许多过去分词已经形容词化了，如be interested in，be excited等，往往表示一个状语，则仍需加Being。
如：As he was filled with new ideas，the young man invented many kinds of mod-ern machines．如果把be filled with理解为be full of是一种状态，则可转换成being filledwith?，如果把be filled理解为单纯的被动，则转换成Filled with new ideas?二者都可。
to improve living conditions.→The question being discussed is about how t o improve living conditions.2.2定语从句可以转化为过去分词如定语从句的谓语是被动语态，或是“系动词+过去分词”结构，且从句的谓语动词所表示的动作或状态是在主句的谓语之前发生或无明确的时间。
此时，我们可以将定语从句转换成过去分词。
有时定语从句谓语虽然是主动语态.但它表示的动作在主句谓语之前就已经完成，这时我们可以将定语从句转换成过去分词。
The report that was made yesterday will be discussed today.→The report made yesterday will be discussed today.The dictionary which my mother bought for me is very useful.→The dictionary bought for me by my mother is very useful.但以下几种情况，一般不可把定语从句转换为分词。
1.虽关系代词作定语从句的主语，但如从句的谓语中含有情态动词，则不能转换成分词。
Those who must hand in their homework before 12 are studying hard now. 此句不宜转成：Those handing in their homework before 12 are studying hard now.2.如关系代词在从句中作主语，且从句谓语是完成时的主动语态，一般不转换成分词。
例：The engineer who has finished his design is about to visit Hawaii.此举不宜转化为：The engineer having finished his design is about to visit Hawaii.3.以关系代词which或as引起的非限制性定语从句，当关系代词指的是前面整个句子，将这个非限制性定语从句转换成分词，其逻辑主语是其前面或后面的整个句子，但分词在这个在句子里结果状语。
例：The boy’s parents died，which left him an orphan.→His parents died，leaving him an orphan.4、用对称，事半功倍。
利用对称性，可以由部分图形的结论得出整个图形的有关结论。
例7、已知：△ABC中，AD是BC上的高，AB=AC=2AD，DE⊥AB，DF⊥AC，E和F是垂足，求证：DE+DF=12BC。
分析：由对称性易证DE=DF，DB=DC，等式DE+DF=BC的两边同除以2，即证DF=DC，在Rt△CDF中易知∠C=30°，DF=DC。
上面的例题说明，有关等腰三角形的问题，有关线段的垂直平分线的问题，以及有关角平分线问题，常常可用对称原理找到解题途径。
例8、△ABC的底边长AB一定，面积一定，何时周长最小？分析：△ABC的底边长和面积一定，则AB边上的高一定，即C点必在与AB平行的直线l上，如图，作A点关于l的对称点A′，易证当A′与点B、点C在一条直线上，即AC=BC时，△ABC的周长最小。
对于一些数学问题，若能洞察到问题所具有的对称性，往往可将问题巧妙转化，使问题思路简捷，化难为易，避繁就简。
表面上看不具有对称性的数学问题，若能巧用问题所蕴含的对称性，往往能突破常规思路，使得解法灵巧，过程简捷，给人一种美的享受。
更容易让学生获得成就感，激发他们的求知欲和学习数学的兴趣。