问题 单项选择题

宽带ISDN可以提供______。
Ⅰ.可视电话 Ⅱ.电子由附 Ⅲ.图文电视  Ⅳ.会议电视 Ⅴ.档案检索
等业务。在这些业务中,属于会话型业务的有______。

A.Ⅰ、Ⅱ和V

B.Ⅲ、Ⅳ和Ⅴ

C.Ⅰ和Ⅳ

D.Ⅰ、Ⅱ、Ⅲ、Ⅳ和Ⅴ

答案

参考答案:C

解析:[知识点] 网络应用技术的发展
[评析] 交互型业务是指在用户间或用户与主机之间提供双向信息交换的业务。它包括下面几种:
1、会话性业务。这种业务以实时性为特点,如可视电话、会议电视。
2、消息性业务。这种业务以非实时性为特征,通过存储转发传递消息,如电子邮件。
3、检索性业务。这种业务是指用户向信息中心索取信息的业务,可选择信息的内容和传输的开始时间,如检索电影、图像、声音和档案等。

阅读理解

阅读理解。

     We can achieve knowledge either actively or passively. We achieve it actively by direct experience,

by testing and proving an idea, or by reasoning.

     We achieve knowledge passively by being told by someone else. Most of the learning that takes place

in the classroom and the kind that happens when we watch TV or read newspapers or magazines is

passive. Conditioned as we are to passive learning, it's not surprising that we depend on it in our

everyday communication with friends and co-workers.

     Unfortunately, passive learning has a serious problem. It makes us tend to accept what we are told

even when it is little more than hearsay and rumor(谣言).

     Did you ever play the game Rumor? It begins when one person writes down a message but doesn't

show it to anyone. Then the person whispers it, word for word, to another person. That person, in turn,

whispers it to still another, and so on, through all the people playing the game. The last person writes

down the message word for word as he or she hears it. Then the two written statements are compared.

Typically, the original message has changed.

     That's what happens in daily life. The simple fact that people repeat a story in their own words

changes the story. Then, too, most people listen imperfectly. And many enjoy adding their own creative

touch to a story, trying to improve on it, stamping(打上标记)it with their own personal style. Yet those

who hear it think they know.

This process is also found among scholars and authors: A statement of opinion by one writer may be

restated as a fact by another, who may in turn be quoted by yet another; and this process may continue,

unless it occurs to someone to question the facts on which the original writer based his opinion or to

challenge the interpretation he placed upon those facts.

1. According to the passage, passive learning may occur in _______.

A. doing a medical experiment    

B. solving a math problem

C. visiting an exhibition    

D. doing scientific reasoning

2. The underlined word "it" in Paragraph 2 refers to _____.

A. active learning

B. knowledge

C. communication    

D. passive learning

3. The author mentions the game Rumor to show that _____.

A. a message may be changed when being passed on 

B. a message should be delivered in different ways

C. people may have problems with their sense of hearing

D. people tend not to believe in what they know as rumor

4. What can we infer from the passage?

A. Active learning is less important.

B. Passive learning may not be reliable.

C. Active learning occurs more frequently.

D. Passive learning is not found among scholars. 

问答题