非限制性定语从句是指用来修饰某一名词或代词的从句，但是这个从句并不起限制或者区分作用。其中，which是一个常用的引导词，下面列举一些which引导的非限制性定语从句的例子。
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The sun, which is a star, provides light and warmth to the earth. （太阳是一颗恒星，为地球提供光和热。）
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The book, which I borrowed from the library, is very interesting. （我从图书馆借的这本书非常有趣。）
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My friend, which I met in college, is now a successful businessman. （我在大学里认识的朋友现在已经成为了成功的商人。）
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The car, which was parked in front of the house, belongs to my neighbor. （停在房子前面的那辆车是我邻居的。）
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The cake, which was made by my mom, was delicious. （我妈妈做的蛋糕非常好吃。）
在上述例句中，which引导的非限制性定语从句可以看做是对前面名词或代词的补充说明。这些句子也可以改写成不使用非限制性定语从句的形式，例如：
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The sun, a star, provides light and warmth to the earth.
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The book I borrowed from the library is very interesting.
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My friend, whom I met in college, is now a successful businessman.
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The car parked in front of the house belongs to my neighbor.
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The cake made by my mom was delicious.
总之，非限制性定语从句的使用可以让句子更加丰富，更具有描述性，同时也能让读者更好地理解所述内容。
