以下のとおりお答えします。
>I can't speak English well enough,and I was here time is shorter than the other guys.
(過去のことですからcanでなくcouldですね。I was here timeは変なので〔the period〕 I stayed hereとしましょう。)
⇒I couldn't speak English well enough, and 〔the period〕I stayed here shorter than the other guys.
>But I was able to spend a wonderful time.
(これでいいと思いますが、「~と思う」を挿入しましょうか。)
⇒But I think I could spend a wonderful time.
>Thank you for all your kindness.
(いいですね。強調するならso muchを入れましょうか。)
⇒Thank you so much for all your kindness.
>Miss you guys already.
(「今はもう」と強調しましょうか。またguys にallやmyをつけて親しみを追加しましょう。)
⇒Now, already I miss you all my guys.
添削文を通して書けばこうなります。
I couldn't speak English well enough, and 〔the period〕 I stayed here shorter than the other guys.
But I think I could spend a wonderful time.
Thank you so much for all your kindness.
Now, already I miss you all my guys.
お礼
遅くなり申し訳ありません。 回答ありがとうございます! とてもわかりやすく助かりました!