加逗号which 通常指代的是逗号前面整句话的内容,不加逗号则指代的是which前最近的那个名词补充一些例子吧。比如 My mother praised me, which made me happy. 这里有逗号，那么which就指代My mother praised me这件事，整句就是妈妈表扬了我这件事让我很高兴。Today I went to the Great Wall which was famous all over the world. 这里没有逗号，which指代the Great Wall 而不是Today I went to the Great Wall这件事，整句就是今天我去了长城，它在世界上很有名。望采纳！