问题 单项选择题

在OSI参考模型中,进行数据加密、解密是由______协议来完成。

A.网络层

B.应用层

C.表示层

D.会话层

答案

参考答案:C

解析:在OSI参考模型中,表示层用于处理在两个通信系统中交换信息的表示方式,主要包括:数据格式转换;数据压缩和解压缩;数据加密和解密。

填空题
完形填空

Our family finally managed to get together, but in a few days we scattered again to the ends of the earth, and I will begin my new job in a new city. My family has never been ___1 _  in this way . When I think about the    2    future, my heart felt grayish. 

When I    3    in the morning, it was raining outside and the sky was as    4    as my mood. My daughter    5    the new skirt that her uncle bought and she flew around the departure hall in the    6     and drew a small and beautiful picture in the dim crowd.

The airplane had a good   7    of newspapers, magazines, television programs, food and drinks. The meal even   8   a serving of Haagen-Dazs ice cream. This small present brightened me up   9    . The gentle smile of the stewardess(空姐)was as beautiful as the   10    after the rain. 

When I    11    the airport, the language that entered my   12   was completely different from what I was   13    three hours ago. Although the street lights were as   14  as Allentown’s, the different clothes and expressions of the people    15     me that I am in a new world. I stood in the busy streets like Alice    16   the world in a fairy tale. My heart was    17    with puzzlement about the uncertain future and longing for the new life. When I   18  being able to do what I like once more, that I will make new    19   and that I can enjoy the fun of exploration. I could not   20  to think about starting my new life.  

1.A.separated                B.gather                C.divided                     D.surprised

2.A.bright                    B.exciting              C.uncertain            D.unusual

3.A.stood up                 B.got up                C.stayed up            D.woke up

4.A.clear                      B.high                   C.dark                   D.gray

5.A.dressed                   B.wore                  C.liked                  D.had

6.A.station                    B.airport               C.port                   D.house

7.A.offer                      B.number                     C.supply                D.amount

8.A.included                 B.contained          C.followed            D.matched

9.A.successfully            B.especially           C.eventually          D.fortunately

10.A.rainbow                B.ground               C.sky                   D.flower

11.A.got on                  B.got off               C.left away            D.took off

12.A.mouth                  B.eyes                   C.mind                  D.ears

13.A.finding                 B.learning             C.hearing                     D.listening

14.A.long                     B.well                   C.brilliant              D.mamy

15.A.told                      B.reminded            C.suggested           D.explained

16.A.visiting                 B.traveling            C.wandering          D.exploring

17.A.full                      B.filled                 C.satisfied             D.pleased

18.A.set about               B.set out                C.thought over              D.thought about

19.A.friends                 B.enemies              C.mistakes             D.progress

20.A.wait                            B.help                   C.decide                D.afford