依句英文點解?

You’re alive that is what matters most, I thought something had happened. 我覺得這句有點寫錯了，請看紅字修正才有意思。 You’re alive是一句statement表示「你仍活著」或當經歷災難後反轉意思說「你沒有死去」。that is what matters most是一組表達對You’re alive的感受「這是最關重要」I thought something had happened.本身是獨立的句子，似乎跟前句那段沒有直接因果或附加關係。它既不是進一步表達為何matters the most「尤關重要」又或解釋「仍活著」的意義，所以文法上無法直接連在most後。最少也要加上，才算合規的句組。這句本身「我想有些事發生了」。就這意思可能是指那人經歷生死存亡而生存下來帶來對人生的改變或因為死過番生而對內心變化。 由於沒有全段其化上文下理，無法準確理解。

I agree with Jenkin.
There are three separate ideas, so they need to be separated by semicolons or full stops.
You're alive. 你還活著。
That is what matters most. 這是最重要的。
I thought something had happened. 我以為發生了事故 (我以為你已經死了)。

This does not seem to be a complete sentence. Did you miss something out ?

The English explanation of what happened are self-explanatory description:-
It means:-
Are you still alive?
Your living is important.
Something had happened to harm your surviving.

你还活着，这就是最重要的，我想你是我的變化

你活著是最重要的事情，我想發生了什麼事。