YOU SAID:
Much has changed in my absence.
INTO JAPANESE
私がいない間、多くのことが変わりました。
BACK INTO ENGLISH
Many things have changed while I was away.
INTO JAPANESE
私が離れている間に、多くのことが変わりました。
BACK INTO ENGLISH
Many things have changed while I was away.
That didn't even make that much sense in English.