Why, every schoolchild knows the answer, You spell out the words.

为什么，每个小学生都知道答案, 你拼写出单词。

This, as every schoolchild knows, is the fundamental difference between being an Animagus, and Transfiguring oneself into an animal.

每个小学生都知道，这是阿尼马格斯和把自己变形为动物的根本区别。