问题 单项选择题


在下列各题的A)、B)、C)、D)四个选项中,只有一个选项是正确的。

在一所大学中,每个系都有自己的局域网,则连接各个系的校园网

A.是广域网

B.还是局域网

C.是地区网

D.这些局域网不能互连

答案

参考答案:B

解析: 广域网是指远距离的计算机互联组成的网络,分布范围可达几千千米乃至上万千米甚至跨越国界、州界、遍及全球范围。局域网是指一个局部区域内的、近距离的计算机互联而成的网络,通常采用有线方式连接,分布范围从几百米到几千米。例如:一座大楼内或相邻的几座楼之间互联的网络。一个单位、学校内部的联网多为局域网。

单项选择题
单项选择题

Another critical factor that plays a part in susceptibility to colds is age. A study done by the University of Michigan School of Public Health revealed particulars that seem to hold true for the general population. Infants are the most cold-ridden group, averaging more than six colds in their first year. Boys have more colds than girls up to age three. After the age of three, girls are more susceptible than boys, and teenage girls average three colds a year to boys’ two.
The general incidence of colds continues to decline into maturity. Elderly people who are in good health have as few as one or two colds annually. One exception is found among people in their twenties, especially women, who show a rise in cold infections, because people in this age group are most likely to have young children. Adults who delay having children until their thirties and forties experience the same sudden increase in cold infections.
The study also found that economics plays an important role. As income increases, the frequency at which colds are reported in the family decreases. Families with the lowest income suffer about a third more colds than families at the upper end. Lower income generally forces people to live in more cramped quarters than those typically occupied by wealthier people, and crowding increases the opportunities for the cold virus to travel from person to person. Low income may also adversely influence diet. The degree to which poor nutrition affects susceptibility to colds is not yet clearly established, but an inadequate diet is suspected of lowering resistance generally.

From the passage, ______ are most likely to catch colds

A.infant boys
B.young girls
C.teenage boys
D.elderly women