Could you plz tell me why the author use the 'not' here? Thx a lot. Here is the paragraph: There are the things I was thinking, son: I had been cross to you. I scolded you as you were dressing for school because you gave your face merely a dab with a towel. I took you to task for not cleaning your shoes. I called out angrily when you threw some of your things on the floor. Why the author said that 'I took you to task for not cleaning your shoes' ? I suppose it should be like: I took you to task for cleaning your shoes. Why did he use the 'not'? Thanks a lot.