添削（内村君）

I would like to go back in the past and study more.

I used to play outside everytime .It was fun for me , but if I study words in English, I will be king of words in English. However , if I change action in my life, I may not meet my friend now, so I must behave such as previous. It is difficult for me to live a freedom. On the other hand , I can remember of my previous life. It makes me so happy. There may be important things in my life. If I remember it, I may not forgot again . This is why I want to go back in the past , but I want to be careful that the future does not change.　

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I would like to go back to the past  and study more.

I used to play outside every day. It was fun for me, but if I had studied English vocabulary more, I could have been very good at it. However, if I change the actions I took in my past, I might not have met my friends now, so I must behave as I did before. It is difficult for me to live freely. On the other hand, I can remember my past life, and that makes me very happy. There are important things in my life, and if I remember them, I may not forget them again. This is why I want to go back in time, but I want to be careful not to change the future.

解説

I would like to go back in the past → I would like to go back to the past.

in→to

everytime → every day

「everytime」は「いつも〜するときに」という意味になるので、ここでは「毎日遊んだ」という意味なら「every day」が正しいです。

if I study words in English, I will be king of words in English → if I had studied English vocabulary more, I could have been very good at it

過去の後悔を表す場合は仮定法過去完了を使います（if + had + 過去分詞）。

「king of words」よりも「very good at it」の方が自然です。ん？kindsかな？

if I change action in my life → if I change the actions I took in my past

「change action」は不自然。「過去に取った行動を変えたら」という意味なら「the actions I took in my past」が正しい。

behave such as previous → behave as I did before

「such as previous」は不自然。「以前のように振る舞う」は「as I did before」。

live a freedom → live freely

「a freedom」は不可算名詞でここでは文法的に不自然。副詞「freely」が正しい。

remember of my previous life → remember my past life

「remember」は前置詞「of」を使わず直接目的語を取ります。

may not forgot again → may not forget them again

「forgot」は過去形で誤り。「forget」が正しい。複数の「重要なこと」を指すなら「them」も必要です。

be careful that the future does not change → be careful not to change the future

「be careful not to …」が正しい構文

改善点

文の最初は必ず大文字

仮定法や時制の使い方を学ぶとより自然な表現になります。

語彙の選択（king of words → very good at it）や副詞の使い方に注意。

文の切れ目（ピリオドやカンマ）の位置に注意すると読みやすくなる。