YOU SAID:

while you were busy translating, I was studying the blade.

INTO JAPANESE

あなたが翻訳に忙しい間、私は刃を勉強していました。

BACK INTO ENGLISH

I was studying blades while you were busy translating.

INTO JAPANESE

あなたが翻訳に忙しい間、私はブレードを勉強していました。

BACK INTO ENGLISH

I was studying blades while you were busy translating.