问英语大虾们一个问题，（比较简单，但对我来说有点难）

Useful is harmful. Extra-curricular Internet can enrich knowledge, good physical and mental. Yet lead to excessive, harmful to health.
中文意思是
有益也有害.上网可以丰富课外知识,愉悦身心.但又会使人沉迷,有害健康.

It's hard to say something.If you spend too much time on it,
it will be harmful.If you use it in the right way,it will be useful.

the internet is a colorful world ,you can learn the useful thing ,but something unheathly can lead you to a harmful world.