He loves his parentsdeeply,both of whom are very kind to him. 解释下这个句子，不是翻译

中的of 是哪个词组提前

both of whom是修饰his parents，把后面这个从句写成完整的简单句就是这样：
Both of his parents are very kind to him.

还有不懂可以问我，祝你学习进步^_^

你好！ 不是提前。both of whom,whom 这里指代parents. 就是both of his parents are very kind to him. 希望对你有所帮助，望采纳。