单选题以下关于Windows操作的叙述中，正确的是 (11) 。

单选题微型计算机中使用的人事档案管理系统，属于下列计算机应用中的 (13) 。

单选题假设用12个二进制位表示数据。它能表示的最大无符号整数为 (3) ；若采用原码，它能表示的最小负整数为 (4) 。

单选题当( )时， TCP 启动快重传。

单选题我国软件著作权受法律保护的期限是 (20) 。一旦保护期限届满，权利自行终止，成为社会公众可以自由使用的知识。

单选题______是指CPU一次可以处理的二进制的位数，它直接关系到计算机的计算精度、速度等指标；运算速度是指计算机每秒能执行的指令条数，通常以______为单位来描述。

单选题下列操作系统中，（12）的主要特性是支持网络系统的功能，并具有透明性。

单选题在模拟音频信道上传输数字信号，必须使用 (25) 。

单选题下列网络互连设备中，属于物理层的是______，属于网络层的是______。

单选题Melissa and LoveLetter made use of the trust that exists between friends orcolleagues．Imagine receiving an (71) from a friend who asks you to open it．This is whathappens with Melissa and several other similar email (72) ．Upon running，such wormsusually proceed to send themselves out to email addresses from the victim’s address book，previous emails，web pages (73) ． As administrators seek to block dangerous email attachments through the recognition ofwell—known (74) ，virus writers use other extensions to circumvent such protection．Executable(.exe)files are renamed to．bat and．cmd plus a whole list of other extensions and wilt still runand successfully infect target users． Frequently，hackers try to penetrate networks by sending an attachment that looks like a flash movie，which，while displaying some cute animation，simultaneouslyruns commands in the background to steal your passwords and give the (75) access to yournetwork． 供选择答案：

单选题在HTML文件中，表格边框的宽度由______属性指定。

单选题Melissa and Love Letter made use of the trust that exists between friends or colleagues. Imagine receiving an (66) from a friend who asks you to open it. This is what happens with Melissa and several other similar email (67) . Upon running, such worms usually proceed to send themselves out to email addresses from the victim' s address book ,previous emails, web pages (68) . As administrators seek to block dangerous email attachments through the recognition of well- known (69) , virus writers use other extensions to circumvent such protection. Executable (.exe) files are renamed to . bat and . cnd plus a whole list of other extensions and will still run and successfully infect target users. Frequently, hackers try to penetrate networks by sending an attachment that looks like a flash movie, which, while displaying some cute animation, simultaneously runs commands in the background to steal your passwords and give the (70) access to your network.

单选题______属于标记语言。 A．PHP B．Lisp C．XML D．SQL

单选题IEEE802.5令牌环网中，时延是由 (36) 决定的。要保证环网的正常运行，整个环网的时延必须大于 (37) 。设有一个令牌环网，长度为400m，环上有28个站，数据速率为4Mbit/s，信号传播速度为200m/μs，每个站点引入1位时延，则环网的最大和最小时延分别为 (38) 和 (39) 。