以下网络地址中属于A类地址的是（）。
A．11.10.20.1
B．194.158.24.1
C．151.142.1.1
D．127.0.0.1
参考答案：A
解析：
[分析]：本题考查IP地址的基础知识。
IP地址是标识Internet上所有计算机的唯一标志。IP地址是由4组被“.”隔开的32位的二进制数，每组是8位二进制数。为表示方便，每组的8位二进制数都用一个十进制数表示，因此常用4组十进制数表示IP地址，每组十进制数的取值范围都是0～255。按照IP地址第一组数值的取值范围，IP地址可以分为A、B、C、D、E这5类，常用的有A、B、C三类。A类地址的第一组数值的范围为1～126，B类地址第一组数值的范围为128～191，C类地址的第一组数值的范围为192～223。
A true friend is always helpful. I didn’t believe it one thing happened to me when I was in Grade 7. Li Jie was one of my classmates. He and I were also neighbours. He always listened to his mother I didn’t like listening to my mother. I didn’t think it was necessary for to teach me anything. Li Jie knew all about that but he said to me. One weekend, Li Jie invited me to watch a film. I liked films very much so I went to the with him happily. The film was about the love between a and her son. After watching it, I began to know how great the love of the mother was. I felt that I didn’t listen to my mother before. I decided to think more about my mother than about . After I told that to him, Li Jie smiled and said, “It’s really necessary for you to watch such a film. That was a good choice (选择) for both you and me.” Suddenly, I knew he invited me to watch the film. Just at that time, I knew a true friend is always .
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