this is kate,whose sister you met yesterday.为什么在sister后不能加whom?this is kate,whose sister whom you met yesterday.为什么不行？

this is kate,whose sister you met yesterday.为什么在sister后不能加whom?
this is kate,whose sister whom you met yesterday.为什么不行？

1 把whom带进句子看看是否合适 this is kate,whom sister you met yesterday.,这样的话定语从句中主语是什么了,既有sister还有 you,所以这样不行
2 whose是形容词性的代词,后面加名词 在这个从句中 whose sister,谁的妹妹,做met的宾语
3 翻译：这是凯特,昨天你见过他的妹妹