求教："有些人说不出哪里好,但是谁都代替不了"怎么翻译?请不要用软件翻译!

some people that you can not tell how good they are,
but you know there is no one can replace them

where can't some people say well
这个一看就是机翻的结果

Some people can not tell where the good, but no one can not substitute

“where can't some people say well, but everybody could not replace”

where can't some people say well, but no one could replace.