问题 单项选择题

关于防火墙的功能,以下描述是错误的。

A.防火墙可以检查进出内部网的通信量

B.防火墙可以使用应用网关技术在应用层上建立协议过滤和转发功能

C.防火墙可以使用过滤技术在网络层对数据包进行选择

D.防火墙可以阻止来自内部的威胁和攻击

答案

参考答案:D

解析:[知识点] 防火墙技术的基本概念[评析] 防火墙是构成网络安全因素的重要手段。它的任务是对于进出网络的所有信息进行全面的检测,监视网络的使用,阻断有害信息进入网络的途径,也要防止内部保密的信息通过一个特别的点传输到系统以外,在必要的情况下发布安全警报,重新部署网络地址转换,向外发布信息。

阅读理解

阅读理解。

     Learning disabilities are disorders in the ways people understand or use language. They can affect the

ability to listen or think, or to speak, or to read, or to write and do mathematics.

     A person with a learning disability has unusual difficulty in developing these skills. Researchers believe

that learning disabilities are caused by differences in the way that the brain works with information. They

say children with learning disabilities are not unintelligent or do not want to work. Their brains just process

information differently than other people. Researchers say that one in five people in America has some kinds

of learning disability. Almost three million children in America receive some kinds of help in school for a

learning disability.

     How can you tell if someone has a learning disability? Experts look for a difference between how well

a child does in school and the level of intelligence or ability of the child. But there is no sign of a disorder.

A few signs of a learning disability include not connecting letters with their sounds or not understanding

what is read. A person with a learning disability may not be able to understand a funny story. They may

not follow directions. They may not read numbers correctly or know how to start a task Different people

have different kinds of learning disabilities. Another may have difficulty understanding what people are

saying. Still another may not be able to express ideas in writing.

     These different kinds of learning disabilities are known by different names. For example, a person who

has difficulty reading may have dyslexia. Someone who cannot do mathematics may have a disorder called

dyscalculia (计算困难).

     Experts say learning disabilities cannot be cured. But people who have them can be helped. Teachers

and parents can help young people with learning disabilities to learn successfully.

1. What does the passage mainly talk about?

A. Some kinds of help in school for a learning disability.

B. How to cure learning disabilities.

C. Causes of learning disabilities.

D. Learning disabilities.

2. It is believed that ____ is the main cause of learning disabilities.

A. different brain

B. unintelligence

C. not wanting to work

D. the way the brain works with information

3. People with learning disabilities may have no trouble ____.

A. understanding a funny story

B. following directions

C. dressing themselves

D. reading numbers correctly  

4. The underlined word in the 4th paragraph probably means ____.

A. difficulty in seeing

B. problem in reading

C. trouble in listening

D. brain disorder

单项选择题