好心人~高手求帮助！
Dear xiaolin
Thank you for writing us about your problems with your parents. I have known this problem between you and your parents. Your parents let you devote time to study and you can’t get along with then.
It is without doubt that you should learn how to get along with your parents. You need to have a talk with them, but the sad truth is that you don’t find a suitable way. The one thing that is clear you parents take care of you very carefully. They looking forward you to get good grades are a good start towards a better future.
As far as I’m concerned, in order to solution this problems you should have a talk with them. You can tell them that you are grown up. You are an adult .I think your parents will understand. What can you do is that let your parents know more about you. I think if you followed this advices will become better.
                                                                                                                                                                                              Your sincerely    

1. Your parents let you devote time to study and you can’t get along with then.
let sb. do是有give permission的意思的，这里感觉不是特别合适，可以用want you devote more time to study.
get along with一般指人际关系之类的，这里也不太合适，如果单纯想表示不同意他们的想法，可能还是but you can't agree with them/ but you can't agree on this好一点

2. but the sad truth is that you don’t find a suitable way.
用haven't

3.The one thing that is clear you parents take care of you very carefully.
这个句子这样写不太对，可以改为：the one thing that is clear is that your parents take very good care of you。

4. They looking forward you to get good grades are a good start towards a better future.
They are looking forward to your getting good grades, which is a good start towards a better future。
或者用一般现在时也可以，意思上有一定区别，be looking forward to 一般表示期待这件事会发生，look forward to表示觉得会喜欢这件事。look forward to后面加名词或者名词词组，一般不加句子。

5.solution this problems
solve this problem

6. You can tell them that you are grown up. You are an adult .
可以改为you are a grown up,但和you are an adult重复，如果两个都保留，则可改为 you have grown up

7. I think if you followed this advices will become better.
I think if you take this advice things will become better

恩，岚君基本上都讲到了，我补充两点。

1. What can you do is that let your parents know more about you.

"What can you do" 应该改成 "What you can do"，以疑问代词引导的从句应该用陈述句语序。

另外，that 改成 to，我觉得读起来更连贯。

2. 最后结尾应该是 "yours sincerely"，顶格写，不用空格。另外下面也要有署名哦~