下面短文中共有10个错误, 请找出并按要求在文中标记并改正在短文下的横线上。
如多一个词：把多余的词用斜线（／）划掉, 在短文下边横线上写出该词, 并也用斜线划掉。
如缺一个词：在缺词处加一个漏字符号（∧）, 在短文下边横线上写出该加的词。
如错一个词：在错的词下划一横线, 在短文下边横线上写出改正后的词。
My grandfather was a teacher. He was the head teacher of a school for boys at the ages of thirteen and eighteen. I know that he was a kind man, because when I am young, he gave me presents, and set me on his knees, and told me stories. And the boys at his school were afraid of him. At school, when he walked into a room full of noise boys, there was silence at once. When he looked at a boy with a certain look in his eye, that boy went red in the face, and looked down his shoes. If a boy brought to him careless work, my grandfather picked up a boy's book and threw it across the room, shouting，“Do it all again, and take it back in the morning！” If the boy was later, or if he forgot to take the work, he had to do it again.