[单项选择]{{B}} Questions 11 to 18 are based on the conversation you have just heard.{{/B}} A. She enjoys standing in line. B. She would go the bank next time. C. She differs from the man. D. She would go home.
参考答案:C 答案解析:[听力原文]
M: I had to stand in line at the bank for about half an hour. There were only two tellers op
第30题: [单项选择]下列关于抽象类的表述中正确的是( )。 A. 派生类必须要实现作为基类的抽象类中的纯虚函数 B. 抽象类的成员函数至少有一个没实现 C. 抽象类不可能用来定义对象 D. 派生类不能成为抽象类 参考答案:C 答案解析:[解析] C++中拥有纯虚函数的类称为抽象类。抽象类不能用采定义对象。如果一个抽象类的派生类没有重定义来自基类的某个纯虚函数，刚该函数在派生类中仍是纯虚函数，该类仍为抽象类。
