定语从句变现分和过分

　　雅思作文评分标准中对句式多样性有明确的要求。如果考生作文想要达到6分，在GRA中要求综合使用简单句式与复杂句式。很多考生会使用定语从句，但是出现的问题也不少，主要有大量使用定语从句，定语从句较短，没有分量。本文希望能帮助学生学习定语从句与分词之间的转化。

　　定语从句在句子中充当定语的作用，通俗上讲，就是用一个句子来修饰某个名词。同样能达到这个作用的有形容词，现在分词以及过去分词。本文主要讨论后两者。

　　一．      定语从句改为现在分词

　　1. They(the two fires) both threatened the nearby town of Los Alamos, home to 15,000 residents and a scientific laboratory, the Los Alamos National Laboratory, which conducts research for the military.(四级unit 4 reading 2)

　　此句中的定语从句修饰前面的Los Alamos National Laboratory，which是这里的引导词，并且这是一个非限制性定语从句。Which在从句中充当主语，这是一个主动语态。我们可以直接将这里的which去掉，然后将conducts改为conducting。因此，此定从可以改为：

　　They(the two fires) both threatened the nearby town of Los Alamos, home to 15,000 residents and a scientific laboratory, the Los Alamos National Laboratory, conducting research for the military.

　　2. People feeling sad or depressed were found to be more likely to set low prices for items they were asked to sell.(四级unit 3 reading 2)

　　Feeling sad or depressed在此句中是现在分词做后置定语，修饰people，feel与people之间是主动关系。并且这里的时态是一般过去时，所以在变从句的时候需要将feeling改为felt过去式。可以推断这里原本的定从应该是：

　　People who felt sad or depressed were found to be more likely to set low prices for items they were asked to sell.

　　简单归纳，定语从句变现在分词，步，从句是否是关系词作主语。第二步，判断从句是否是主动语态。第三步，去掉关系词并将从句中谓语动词改为现在分词。

　　Pleasure and displeasure are two emotions that serve this function.(四级unit 3 reading 2)

　　改：Pleasure and displeasure are two emotions serving this function.

　　A pandemic is an outbreak of a disease that rapidly leads to large numbers of people being affected.(四级unit 6 reading 1)

　　改：A pandemic is an outbreak of a disease rapidly leading to large numbers of people being affected.

　　3. In fact, artists who value the wabi-sabi aesthetic create works that are deliberately imperfect.(四级unit 2 reading 1)

　　此句有两处定从，并且关系词在其中都是主语，但是区别是第二处定从是一个主系表结构。如果定从是主系表，那我们可以直接去掉主语和系动词，将表语部分的形容词拿到被修饰对象前面做定语。所以此句改为：

　　In fact, artists valuing the wabi-sabi aesthetic create deliberately imperfect works.

　　综上所述，现在分词做后置定语中，这个分词与句子主语是主动关系，并且现在分词可以表示一般现在时，一般过去时，现在（过去）进行时。以下例子为从句是现在进行时。

　　One country in particular that is facing wildfire problem is the United States.(四级unit 4 reading 1)（现在进行时，直接去掉引导词和be动词）

　　改：One country in particular facing wildfire problem is the United States.

　　如果从句是完成时态，则将从句部分改为having done的结构。学生容易将这里的done和被动语态中的done混淆，这里主要是时态决定的完成时态。

　　Around the world there have been many outbreaks of cholera that have killed millions of people.(四级unit 6 reading 1)

　　改：Around the world there have been many outbreaks of cholera having killed millions of people.

　　二． 定语从句改为过去分词

　　当定语从句属于被动语态时，并且时态为一般现在时，一般过去时以及进行时态时，可以将引导词和be动词去掉，只留下过去分词做后置定语来修饰前面的先行词。但是，如果时态是完成时态时，这里就需要变成having been done，学生最容易犯错的便是完成时态。

　　1. Cholera is a disease that is transmitted by drinking water contaminated with bacteria.(四级unit 6 reading 1)

　　改：Cholera is a disease transmitted by drinking water contaminated with bacteria.

　　此句中本来便存在一个过去分词做后置定语，那便是contaminated with bacteria，这里修饰的时前面的drinking water。若改为定语从句应该是which/that is contaminated by bacteria.

　　2. This organization sponsors scientific research aimed at sustainable development of the area.(四级unit 5 reading 2)

　　在理解此句时，学生会直接认为aimed at是谓语动词，实际上这里的谓语动词应该是sponsors，后面的aimed at是后置定语，修饰前面的research。再如以下句子。

　　Even areas not affected by the disease saw a drop in tourism as people became concerned about the spread of SARS and fearful of flying in general.(四级unit 6 reading 2)

　　此处not affected by the disease便是过去分词修饰areas。这句中使用的是否定结构，否定结构中的否定词用在分词前面。下句中的related to也是过去分词作后置定语修饰先行词legislation。

　　So far, the council has passed legislation related to search-and-rescue missions and issues surrounding ocean pollution.(四级unit 5 reading 2)

　　3. It is thought to be accepted by the whole society and something that is recognized and maintained by powers such as the police.(四级unit 8 reading 1) （直接去掉that is）

　　改：It is thought to be accepted by the whole society and something recognized and maintained by powers such as the police.

　　这类句子改为过去分词作后置定语比改现在分词简单些，关键是学生需要理解中间的被动语态，也就是这里判断出该从句为非完成时态时，直接将引导词和be动词去掉就可以。

　　Until now there have not been any detection from the few stars which have been searched.(剑9 Test 1 reading 2)

　　该句便出现了现在完成时的被动语态，学生遇到这类句子其实是比较容易理解的，但是如果该句子改为分词做后置定语则为:

　　Until now there have not been any detection from the few stars having been searched.

　　定语从句和分词作定语两个内容不仅再阅读中会使学生难以理解，并且学好之后还可以提高写作的句子多样性，因此，可以根据留预教材中这些出现的句子帮助学生归纳总结这类用法，帮助学生理解也让学生学会使用分词作定语的用法。更多雅思写作干货敬请关注新航道雅思考试频道