YOU SAID:
i was doing your mum last night
INTO JAPANESE
私は昨夜あなたのお母さんをやっていた
BACK INTO ENGLISH
I was doing your mother last night.
INTO JAPANESE
私は昨夜、あなたのお母さんをやっていた。
BACK INTO ENGLISH
I was doing your mother last night.
You've done this before, haven't you.