I don‘t know her 为什么最后要用her不是用she

I don't know her I don't know her,but I know her name.为什么用her不用his为什么是性别不同 I don't know her.I'll give it to ber.为什么这两句都用her呢?说明 I don't know his我不认识他是这样说的 为什么女的就是 I don't know her I don‘t know her 为什么最后要用her不是用she 为什么?I dont know her.后面有用her,而不是she呢? I really don't know her和I don't really know her的区别 I don't(know)the teacher,but I(know about)her.可以换成know about;know? I don't(know)the teacher,but I(know about)her.可以换成know about ; know? 改为同义句：I don’t know what I should buy her.I don't know _____ _____ buy her. I don't know her telephone number的意思 sorry I don't know her last name同义句 对I don't know her name.提问 I don’t know her address,（ ）I can’t write to her. I don't know. Lucy hasn't come yet.I don't know what______(happen) to her.答案是has happened ,为什么呢? （i don't know her name i know she is 19 years i don't know her,（ ） i’ve known her for two years