曼切斯特编码的特点是（请作答此空），它的编码效率是（）
A.在"0"比特的前沿有电平翻转，在"1"比特的前沿没有电平翻转
B.在"1"比特的前沿有电平翻转，在"0"比特的前沿没有电平翻转
C.在每个比特的前沿有电平翻转
D.在每个比特的中间有电平翻转

在HTML中，预格式化标记是（）。
A.
B.

一台主机的IP地址为202.113.25.36，掩码为255.255.255.0。如果该主机需要向网络202.113.26.0进行直接广播，那么应该使用的源地址为
A.202.113.26.0
B.202.113.26.255
C.202.113.25.36
D.202.113.25.255

In multipoint networks , there are tree persistence methods when a station finds a channel busy.in the 1-persistent method,after the station finds the line idle,it sends its frame immediately.this method has the （请作答此空） chance of collision because two or more stations may find the line （） and send their frames immediately. In the nonpersistent method , a station that has a frame to send （） the line . If the line is idle , it sends immediately If the line is not idle , it waits a （） amount of time and then senses the line again.The nonpersistent approach （） the chance of collision because it is unlikely that two or more stations will wait the same amount of time and retry to send simultaneously The p-persistent approach combines the advantages of the other two strategies . It reduces the chance of collision and improves efficiency.
A.the lowest
B.the highest
C.possible
D.no

在Excel的A1单元格中输入函数=”round(14.9,0)”,按回车键之后，A1中的值为（）。
A.10
B.14.9
C.13.9
D.15

要在页面中实现多行文本输入，应使用（）表单。
A.text
B.textarea
C.select
D.list