Disagreement among so-called professionals
Disagreement among so-called professionals does not speak against the idea that there are correct and incorrect forms. This merely demosntrates the depths to which our education system has sunk. When I was about that age a similar thing happened to me. I did not accept the marking, however. Instead my mother leapt to my aid and proved every one of the teacher's corrections to be wrong and found a further mistake in his comments. He was an M.A. in English! Here here to the comments made below!