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) 。

单选题在www中，用于对信息寻址的是______。 A．HTTP B．HTML C．XML D．URL

单选题在Linux系统中，某文件的访问权限信息为“-rwxr-xr-x”，下列对该文件说明中正确的是______。

单选题若对二进制整数x和y的各位进行异或运算后的结果为全0，则说明______。 A．x＞y B．x＜y C．x＝y D．x＝-y

单选题以太网中使用的校验码标准是 (24) 。

单选题配置IP地址池的名称采用的命令是______。

单选题当用浏览器查看网站时，主页标题显示在 ________ 。

单选题在SNMPv1 中， （ ） 操作是由代理发给管理者的响应。