India is a country with at least fifty major regional languages, fourteen of which are officially recognized.

这是大全446答案，对这个语法现象不是非常明白，非限制性定语从句which引导，或介词+ which引导，这个算什么语法现象呢？

请问这类用法可以用在限制性定语从句中吗？

如： I picked up the apples some of which are badly bruised.

张道真曰：

在非限制性定语从句中，which和whom 常可和of 或其他介词连用。

two-thirds of which are..

most of which.

some of which

one of which

three of whom

我觉得是同位语. fourteen of which are officially recognized. 进一步修饰前面的language.

我认为这不是同位语，从句，ｗｈｉｃｈ作介词ｏｆ的宾语，而同位语从句的引导词是不做成分的

India is a country with at least fifty major regional languages　ｔｈａｔ　 fourteen of ｔｈｏｓｅ　ｌａｎｇｕａｇｅ are officially recognized.

不知道上面的修改是不是正确的同位语形式？

此外在ｔｈａｔ前面可以加逗号吗　？或者说非限制性同位语从句可以用ｔｈａｔ引导马？