Момогите в косвенную речь перевести. "don't be silly, harry", his mother said."you have to go. you're quite well, and you still have important things to learn. and besides that, you're the headmaster of the school".

Harry's mother told him not to be silly. She said that he had to go. Then she added that he was quite well and he still had important things to learn. In addition to it, she reminded him that he was the headmaster of the school.