第51题： 某简单无向连通图G的顶点数为n，则图G最少和最多分别有（  ）条边。
A.n,n2/2
B.n-1,n*(n-1)/2
C.n,n*(n-1)/2
D.n-1,n2/2
答案解析与讨论：www.cnitpm.com/st/4513682.html

第52题： 根据渐进分析，表达式序列：n4, lgn, 2n, 1000n, n2/3, n!从低到高排序为（  ）。
A.Ign,1000n, n2/3, n4, n!, 2n
B.n2/3,1000n, lgn, n4, n!, 2n
C.lgn,1000n, n2/3, 2n, n4, n!
D.Ign, n2/3, 1000n, n4, 2n, n!
答案解析与讨论：www.cnitpm.com/st/4513721316.html

第53题： 采用DHCP动态分配IP地址，如果某主机开机后没有得到DHCP服务器的响应。则该主机获取的IP地址属于网络（  ）。
A.202.117.0.0/24
B.192.168.1.0/24
C.172.16.0.0/16
D.169.254.0.0/16
答案解析与讨论：www.cnitpm.com/st/4513828950.html

第55题： 当修改邮件时，客户与POP3服务器之间通过（  ）建立连接，所使用的端口是（  ）。
1)A.HTTP
B.TCP
C.UDP
D.HTTPS
2)A.52
B.25
C.1100
D.110
答案解析与讨论：www.cnitpm.com/st/4514016691.html

第56题： 因特网中的域名系统(Domain Name System)是一个分层的域名，在根域下面是顶级域，以下顶级域中，（  ）属于国家顶级域。
A.NET
B.EDU
C.COM
D.UK
答案解析与讨论：www.cnitpm.com/st/4514117366.html

第57题： Regardless of how wellDesigned,Constructed,And testedA system orApplication mayBe, errors orBugs will inevitably occur. OnceA system hasBeen（  ），it enters operationsAnd support.
Systems support is the ongoing technical support for user,As wellAs the maintenance required to fixAny errors, omissions,or new requirements that mayArise.BeforeAn information systemCanBe（  ）, it mustBe in operation. System operation is theDay-to-day, week-to-week, month-to-month,And year-t-year（  ）ofAn information system'sBusiness processesAndApplication programs.
Unlike systemsAnalysis,Design,And implementation, systems supportCannot sensiblyBe（  ）intoActual phases thatA support project must perform. Rather, systems supportConsists of four ongoingActivities thatAre program maintenance, system recovery, technical support,And system enhancement.EachActivity isA type of support project that is（  ）byA particular problem,event, or opportunity encountered with the implemented system.
1)A.designed
B.implemented
C.investigated
D.analyzed
2)A.supported
B.tested
C.implemented
D.constructed
3)A.construction
B.maintenance
C.execution
D.implementation
4)A.broke
B.formed
C.composed
D.decomposed
5)A.triggered
B.leaded
C.caused
D.produced
答案解析与讨论：www.cnitpm.com/st/4514216784.html