—Mum, I’ve been doing my homework for two hours.    I play computer games for an hour?

—No, I’m afraid not. You’d better go out for a walk. It does good to your eyes.

A．Can’t

B．Wouldn’t

C．May not

D．Won’t

如果有一个类MyFrame是Frame的子类，能够被不同包中的类所使用，请写出该类的声明头： 【7】 。