—What do you want to be when you grow up?

—I want to be _________ social worker. Many people are in great need of our help.[ ]

A. a              

B. an          

C. the            

D. 不填

一个类可以从直接或间接的祖先中继承所有属性和方法。采用这个方法提高了软件的
【3】 。