什么叫非限制性定语从句?English举个例子 别太深了

非限定性定语从句的作用是对所修饰的成分作进一步说明,通常是引导词和先行词之间用逗号隔开,将从句拿掉后其他部分仍可成立
Charles Smith,who was my former teacher,retired last year.查理·史密斯去年退休了,他曾经是我的老师.
这句就是非限制性定语从句,去掉 who was my former teacher后,句子的表意依然清楚
There is somebody here who wants to speak to you这里有人要和你说话,这句话是限制性定语从句,去掉who wants to speak to you后句子的表意就不清楚了.
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