问题 单项选择题

Electronic mail has become an extremely important and popular means of communication.
The convenience and efficiency of electronic mail are threatened by the extremely rapid growth in the volume of unsolicited commercial electronic mail. Unsolicited commercial electronic mail is currently estimated to account for over half of all electronic mail traffic, up from an estimated 7 percent in 2001, and the volume continues to rise. Most of these messages are fraudulent or deceptive in one or more respects.
The receipt of unsolicited commercial electronic mail may result in costs to recipients who cannot refuse to accept such mail and who incur costs for the storage of such mail, or for the time spent accessing, reviewing, and discarding such mail, or for both. The receipt of a large number of unwanted messages also decreases the convenience of electronic mail and creates a risk that wanted electronic mail messages, both commercial and noncommercial, will be lost, overlooked, or discarded amidst the larger volume of unwanted messages, thus reducing the reliability and usefulness of electronic mail to the recipient. Some commercial electronic mail contains material that many recipients may consider vulgar or pornographic in nature.
The growth in unsolicited commercial electronic mail imposes significant monetary costs on providers of Internet access services, businesses, and educational and nonprofit institutions that carry and receive such mail, as there is a finite volume of mail that such providers, businesses, and institutions can handle without further investment in infrastructure. Many senders of unsolicited commercial electronic mail purposefully disguise the source of such mail.
Many senders of unsolicited commercial electronic mail purposefully include misleading information in the messages’ subject lines in order to induce the recipients to view the messages. While some senders of commercial electronic mail messages provide simple and reliable ways for recipients to reject (or ’opt-out’ of) receipt of commercial electronic mail from such senders in the future, other senders provide no such ’opt-out’ mechanism, or refuse to honor the requests of recipients not to receive electronic mail from such senders in the future, or both.
Many senders of bulk unsolicited commercial electronic mail use computer programs to gather large numbers of electronic mail addresses on an automated basis from Internet websites or online services where users must post their addresses in order to make full use of the website or service.
The problems associated with the rapid growth and abuse of unsolicited commercial electronic mail cannot be solved by the government alone. The development and adoption of technological approaches and the pursuit of cooperative efforts with other countries will be necessary as well.

According to the passage, efficiency of e-mail is threatened by ______.

A.heavy e-mail traffic

B.fraudulent e-mail messages

C.large volume of messages

D.increasing amount of unwanted e-mail

答案

参考答案:D

解析: 本题考查细节理解。根据文章第二段第一句“The convenience and efficiency of electronic mail are threatened by unsolicited commercial electronic mail”,从第三段得知unsolicited commercial electronic mail指的是unwanted messages。所以,答案是D。

单项选择题

近几年,通信技术网络的超高速化,已成为世界上的发展潮流,空间技术与计算机融合成跨越时间与空间的信息基础结构,它将逐渐深入千家万户,从根本上改变人们的生产、生活和相互交往的方式,加速人类文明和文化的传播,增进相互理解和全球意识。 空间信息的高速公路,这一名词是借鉴信息高速公路概念,也是信息高速公路的拓宽与延伸。

所谓空间信息高速公路,我们可以形象地将它理解为以卫星、光纤再辅之以其他通信手段作为“公路”,而以集电脑、电话、传真等为一体的多媒体作为“汽车”,使信息高速传递并能共享的通信网络。这种网络遍布全国乃至全球。我国则将它称之为国家经济信息化基础设施,其内涵包括4项要素:网络与通信、计算机与信息化设备、信息资源与服务、人与信息化环境。   

卫星通信和数字网络光缆就像高速公路一样,是促进社会经济发展的基础设施。它不仅包括地面光缆数字通信网络系统,而且还包括通信卫星、卫星定位系统和环境、灾害监测技术系统。此外,还有不断更新的社会、经济统计数据库和自然资源数据系列,以及宏观调控、规则决策和工程设计服务及知识库,逻辑推理机等人工专家系统,这样,才能有效地实现以信息交流代替人流、物流与能量流。   

加速发展空间技术,多方面、高效率地利用空间技术,特别是充分利用空间信息资源,促进社会生产力的发展,已成为当今世界的共识。通信卫星具有通信容量()、可靠性 ()、传输距离()、不受地理环境影响等许多优点,所以备受各国的重视和欢迎。在空间信息高速公路中,卫星无线电信频率宽,极容易实现双向高速率的数据和可视电信业务,并适用于单相多路的电视节目以及新闻报道,对大多数用户都有实用价值。

对发展中国家来说,空间信息高速公路的建设,可弥补通信基础设施差与区域性通信空缺之不足。例如,地面信息高速公路的成本昂贵,需要10—15年甚至更长时间才能建成,是一个无法在短期内普及服务的巨额投资项目,而卫星接收设备费用大约只需200美元,其技术是现成的,是一个在短期内便能普及并能满足绝大多数用户需求的业务项目。

在文中括号内填上恰当的词语是()。

A.大,高,远

B.多,高,近

C.大,强,小

D.小,低,远

问答题 简答题