41● TCP/IP协议分为四层，分别为应用层、传输层、网际层和网络接口层。不属于应用层协议的是（62） ，属于网际层协议的是（63） 。
A.SNMP
B.UDP
C.TELNET
D.FTP
开始考试练习点击查看答案42● 一个局域网中某台主机的IP地址为176.68.160.12，使用22位作为网络地址，那么该局域网的子网掩码为（64） ，最多可以连接的主机数为（65） 。
A.255.255.255.0
B.255.255.248.0
C.255.255.252.0
D.255.255.0.0
开始考试练习点击查看答案43● DOM is a platform-and language-(66) API that allows programs and scripts to dynamically access and update the content,structure and style of WWW documents (currently,definitions for HTML and XML documents are part of the specification).The document can be further processed and the results of that processing can be incorporated back into the presented (67) .DOM is a (68) -based API to documents,which requires the whole document to be represented in (69) while processing it.A simpler alternative to DOM is the event-based SAX ,which can be used to process very large (70) documents that do not fit into the memory available for processing.
A.specific
B.neutral
C.contained
D.related
开始考试练习点击查看答案44● Melissa and LoveLetter made use of the trust that exists between or colleagues.Imagine receiving an (71) from a friend who asks you to open it.This is what happens with Melissa and several other similar email (72) .Upon running,such worms usually proceed to send themselves out to email addresses from the victim’address book,previous emails,web pages (73) . As administrators seek to block dangerous email attachments through the recognition of well-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 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 passwouds and give the (75) access to your network.
A.attachment
B.packet
C.datagram
D.message
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