大型组织一般都有自己的电信网络来传送和接收声音、数据和图像。然而，小型组织不可能投资建设自己的网络，他们通常使用的是（）。
A．公用交换线路
B．快速分组交换机
C．标准电子邮件系统
D．因特网
参考答案：A
解析：
公司使用公共交换线路作为传输基础，这是低数据量用户之间进行通信的最合理成本方式。选项(b)不正确，因为快速分组交换机接收来自不同设备的数据，将数据分割成包，然后将其通过网络传输到目的端。公共交换线路由电信公司和其他自己拥有网络的大公司进行安装。选项(c)不正确，因为电子邮件没有进行语音和数据传输的能力。选项(d)不正确，因为因特网不提供电话连接。
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| Like most people, I was brought up to look upon life as a process of getting. It was not until in my late thirties that I made this important 1 : giving-away makes life so much more exciting. You need not worry if you 2 money. This is how I 3 with giving away. If an idea of improving the window display of a neighborhood store 4 to me, I step in and make the suggestion to the 5 . If a car accident happens, I think the 6 will be needed, so I 7 them up and tell them about it, though I am not in 8 here. One discovery I made about this world is to give 9 getting something back, though the 10 often comes in an unexpected form. One Sunday morning the local post office delivered an important 11 letter to my home, though it was 12 to me at my office. I wrote the postmaster a note of 13 . More than a year later I needed a post-office box for a new business I was 14 . I was told at the window that there were 15 boxes left, and that my name would have to go on a long 16 list. As I was about to 17 , the postmaster appeared in the 18 . "Wasn't it you that wrote us that letter a year ago about delivering a special delivery to your home?" I said it was. "Well, certainly you are going to have a box in this post office 19 we make one for you. You don't know what a letter like that means to us. We usually get 20 but complaints." | ||||
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