(C)

    Hello, boys and girls! My name is Dick. I'm a boy. I'm a robot (机器人). Please look here. These are my hands. My arms are long. I have no hair. This is my face. I have two big eyes, a long nose and a wide mouth. Here are my big ears. ⑶I have short legs and two big 　　 (foot). I can walk(步行). I can speak Chinese, but I can't speak English. I'm your good friend.

计算$\frac{a^2}{a-b}-\frac{b^2}{a-b}$的结果为（　　）

漫画《认识自己》告诉人们（    ）