托福语法讲解——定语从句

什么是定语从句？

定语从句是指在句子中修饰或限定某一名词或代词的从句，被修饰的词叫先行词。

示例

正在打电话的那个女孩子最漂亮。

That girl is making a phone call and she is the most beautiful one.

→The girl who is making a phone call is the most beautiful one.

为什么要用定语从句？

（1）对句子中的名词或相当于名词的词进行具体说明时

示例

Tony is studying online courses at Koolearn.

→Tony，who is going to Harvard University next year，is studying online courses that can improve his English skills at Koolearn.

（2）连接句子

示例

从前有座山，山里有座庙，庙里有个老和尚，老和尚在给小和尚讲故事。

Once there was a mountain.On the top of the mountain there was a temple.In the temple there was an old monk.The old monk was telling a story to a young monk.

→Once there was a mountain，on the top of which there was a temple，in which there was an old monk，who was telling a story to a young monk.

引导定语从句的关系词

关系代词

（1）who，whom，whose，that

示例

Tony was the only boy in the class who became an astronaut.

Tony was the boy whom/that I saw yesterday.

They rushed to help Tony whose hair was caught in the door.

（2）which， that

示例

The new hairstyle which is very popular among young students is designed by Tony.

当先行词被最高级、表示程度的词、序数词等修饰的时候，用that

示例

The hairstyle is the best one that I have ever had.Please tell me anything that you know about Tony.

介词+which

示例

The house which Tony lives in is very big.

→The house in which Tony lives is very big.

关系副词

when，where，why

示例

Where were occasions when Tony felt inspirations were gone.

Chengdu is the place where Tony found the inspirations for his new art work.

Is this the reason why he choose to say？

注：用关系代词还是关系副词，要看后面的句子完不完整。使用关系副词时，后面的句子是完整的。

限制性定语从句和非限制性定语从句

限制性定语从句表示“多选一”的概念，使笼统模糊变得具体化；非限制性定语从句表示进一步补充说明

找出定语从句及先行词

示例

In some very old star systems，which formed before many heavy elements were produced，the heavy-element share may be less than 0.1 percent.

The substancesthat make up both groups of planets are divided into three groups——gases，rocks，and ices——based on their melting points.

Thus，planetesimanls（星子）everywhere should contain the elements needed for life，which means that objects built from planetesimanls——planets，moons，asteroids，and comets——also contain these elements.

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