I had to do my homework. I could not help my mother with the washing-up. A. Because I was busy doing my homework, I could not help my mother with the washing-up. B. It was impossible for m

Because I was busy doing my homework, I could not help my mother with the washing-up.

It was impossible for me to do my homework although my mother helped me with the washing-up.

I could not help my mother with the washing-up until I finished my homework.

I could not do my homework because I had to help my mother with the washing-up.