Something in italki

I'm a mechanical engineer.This is my first time writing something on italki.
I was just browsing some items and comments,and I found that some comments just shows a new sentence without explaining the correction. This will confuse language learners.Sometimes,the sentences written by language learners is correct but just not idiomatic,if there is no explanation,they won't know if it's right or wrong.
So, I have some suggestions:
1. Write sentences and give comments using two languages.
2.No explanation , no comment.
Why do we need to learn a foreign language? I thought a lot.The most fundamental must be that we want to know some different, we want to communicate with each other,we want to know each other. So,don't worry about if it‘s idiomatic,need care if it is understood. Most of the time, we can understand the mean the writer want to express. Then just say "Good job！" or "You are right,and I have a better one for you reference".Of course,you should point out the mistakes in principle if they did have any.

Thanks for Soh kaiwen's helf! The highlinghted is the correction.

多谢苏凯文的帮忙！