YOU SAID:
I regret what I did last night.
INTO JAPANESE
私は昨夜やったことを後悔しています。
BACK INTO ENGLISH
I regret what I did last night.
INTO JAPANESE
私は昨夜やったことを後悔しています。
BACK INTO ENGLISH
I regret what I did last night.
That didn't even make that much sense in English.