:) ! расстройке скобки, поставив глагол в нужную форму, задайте общий вопрос и постройте отрицание. в скобках укажите время. i (to read) the book, when my mother came.

I was reading the book when my mum came. (Past Continuous, Past Simple)
Was I reading the book when my mum came?
I wasn't reading the book when my mum came.