问题 单项选择题

VLAN在现代组网技术中占有重要地位,若一个局域网由多个VLAN组成,下列说法不正确的是()。

A.当站点从一个VLAN转移到另一个VLAN时,可以不改变物理连接

B.VLAN中的一个站点可以和另一个VLAN中的站点直接通信

C.当站点在一个VLAN中广播时,其他VLAN中的站点不能收到

D.VLAN可以通过MAC地址、交换机端口等进行定义

答案

参考答案:B

解析:

VLAN是建立在局域网交换机和ATM交换机之上的,它以软件方式来实现逻辑工作组的划分与管理,逻辑工作组的结点组成不受物理位置的限制。当站点从一个VLAN转移到另一个VLAN时,只需要通过软件设置,而不需要改变它的物理连接。

VLAN中的一个站点不可以直接和另一个VLAN中的站点通信。当站点在一个VLAN中广播时,其他VLAN中的站点不能收到。VLAN可以通过MAC地址、交换机端口等进行定义。本题选择答案B正确。

单项选择题
阅读理解

第三部分:阅读理解(共对小题;每小题2分,满分物分)

阅读下列短文,从每题所给的四个选项(A、B、C和D中,选出最佳选项,并在答题卡上将该项涂黑。

Relation between the United States and Columbia suffered for many years because of an incident involving the Republic of Panama. By the end of the Spanish-American War in 1898, many Americans felt that an easier and faster way was needed to get ships from the Atlantic Ocean to the Pacific Ocean. Some people in the United States first believed that a canal across Nicaragua was the answer. However, President Theodore Roosevelt decided that a canal through Panama would be a better choice.

In order to build the canal , the United States had to negotiate (谈判) a treaty with Columbia , which at that time controlled Panama . Roosevelt offered Columbia $ 10 million plus $ 250,000 a year for 99 years for a six-mile-wide strip of land across Panama. Columbia rejected the United States’ offer. This ranged President Roosevelt, and negotiations with Columbia ended.

In 1903, a revolution broke out in Panama. The United States ships were sent by President Roosevelt to protect the Panamanian revolutionaries from Columbian forces. The revolution succeeded, and Panama declared its independence from Columbia. The United States then negotiated with the newly formed government. A treaty was signed, and the United States began building the canal.

As a result of the incident, Columbia and the United States remained on bad terms for many years. Not until 1921, when the United States agreed to pay Columbia some compensation (赔偿) for its territory, did relations between the two countries improve.

56. According to the passage, the United States and Columbia were on bad terms because the United States had ________.

A. at first wished to build a canal through Nicaragua

B. promised to pay Columbia $ 10 million for Panama

C. wished to build a canal through Panama

D. supported Panamanian revolutionaries in their fight for independence from Columbia.

57.  From the information in the passage, it can be concluded that the United States ______.

A. wanted to build a canal because it was considered starting a war

B. felt that building a canal through Panama was worth the risk of ruining relations with Columbia

C. believed that a canal through Nicaragua would be profitable

D. had lost the Spanish-American War

58.  It can be inferred from the passage that an important reason for the decision of the United States to build a canal was to _______.

A. develop trade relations with Europe

B. improve relations with South American countries

C. prevent European ships from reaching the Pacific Ocean

D. reduce travel time for its ships in case of war

59. The passage mainly gives us________.

A. advice                    B. information               C. humor        D. news