I have bought the new mp3 for three days.这句话有什么语病哪?（单句改错）

I have bought the new mp3 for three days.这句话有什么语病哪?（单句改错） 给I have come here for three days改错 单句改错求讲解1This is the most expensive pen which I have bought.2 Have a look for the picture.(单句改错） 改错：what advance equipments have they bought for the new fact 改错：They have yet bought their new books for school I bought the book three days ago的同意句 单句改错：I have been known to faint for the sight of blood I have the book for two days.用borrowed,bought,lent,kept哪个?为什 I have already bought the book for about two years.这句话错在哪里? I have bought the coat for 8 months.这句话对吗?我总觉得不对,感觉I have ha Look!Someone sleeps on the soft sleeper!英语改错这句话有什么语病?