问题 问答题 简答题

简述局域网中三层交换技术主要分类及其功能。

答案

参考答案:

一类是以流为基础的,这种技术基于流高速缓存进行数据转发,它除了必要的路由查找过程外,大部分数据转发过程通过第二层交换处理。另一类是基于特别设计的硬件来实现逐包查找的,这里的硬件通常是指CAM芯片或ASIC芯片,这类技术的特点是每一个包都要进行路由查找。

阅读理解

The world’s greatest detective, Sherlock Holmes, is back on our screens.

The new BBC TV series of Sherlock was broadcast in the UK on Jan 1. But the history of Sherlock dates back 127 years.

Since the creation of Holmes in 1887, he has been taking us on adventures (冒险) one after another.

The Sherlock series is a playful drama, covered in crimes and mystery. It gives us a modern Sherlock for a new generation, who solves cases with the help of the Internet, cell phones and GPS.

People look to Sherlock for both adventure and inspiration (灵感). Each case sends us on a mysterious journey with Holmes. The stories give life and color to our imagination: as he checks the crime scene, we join him and become detectives too, looking out for hidden clues.

Yet Holmes is no Superman. He cannot fly, or turn invisible (隐形的). But his powers are within all of us: reason, logical thinking and paying attention to detail. While an artist’s painting is his art, Sherlock’s art is his intelligence (聪明才智). He is human, and this is what makes Holmes a true hero for all of us.

In the new series of Sherlock, most people thought Holmes was dead. But he returns after two years of hiding in the shadows. Now the whole city of London is in danger. What can Holmes possibly do? Uncover the mystery yourself by watching the new series!

小题1:Sherlock was created in _________.

A.2014

B.1973

C.1887

D.1900小题2: From the passage, we learn that Sherlock Holmes _________.

A.invites some of his friends to help him with cases

B.refuses to use modern technology

C.has super powers that helped many people

D.is admired for his intelligence小题3:In the new series of Sherlock, Holmes returns after _________.

A.dying

B.getting a special power

C.hiding

D.going abroad小题4: The writer wrote the passage to __________.

A.compare Sherlock Holmes with Superman

B.explain how Holmes solves cases

C.ask people to learn from Sherlock Holmes

D.explain why Holmes is so popular小题5: Where can you probably read the article?

A.TV Guide.

B.Science fiction book.

C.Detective stories.

D.Travel Guide.

单项选择题