简单定语从句改错题The book,which cover is broken ,is not mine.这句话有错吗?

简单定语从句改错题The book,which cover is broken ,is not mine.这句话有错吗?我始终没看出来!还有这句话“Who is the man who is talking with you”这句话感觉读起来不顺,感觉不出来哪错了!注意：每句只有一个错误