the machine has been used for several years.It needs repairi

need doing = need to be done,所以后面用动名词形式是对的,也可以写成另一种形式,即被动形式的,同义句为
The machine has been used for several years.It needs to be repaired.
翻译：这个机器已经用了好几年了,它需要修理了.
有不明白的请继续追问,