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问题 单项选择题

实现安全电子邮件，有端到端的安全电子邮件技术、（），还需要有安全可靠的邮件服务器。

A.网络层的安全电子邮件技术

B.链路层的安全电子邮件技术

C.传输层的安全电子邮件技术

D.应用层的安全电子邮件技术

答案

参考答案：C

填空题

设有如下表： 学生(学生号N(3)，姓名C(3)，性别C(1)，年龄N(2)) 课程(课程号C(3)，课程名称C(3)，教师C(3)) 选课(学生号N(3)，课程号C(3)，成绩N(3)) 请对下面的SQL语句填空： CREATE TABLE学生 【33】

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单项选择题

In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.

In recent years, there has been a dramatic increase in the range of media used to (71) information. Initially, communication was limited to simple forms of (72) such as voice and paper. This century, however, has witnessed the introduction of a greater variety of media types such as the telephone and visual forms of media. In the latter part of the century, this trend has accelerated and there is now a wide range of media types available to convey information. These advances provide a great opportunity for new developments in a range of areas such as education and commerce. However, there are also a number of problems associated with the growth of (73) in society. In particular, there is a great danger of creating information (74) . This problem can be seen, for example, in business where executives are required to make decisions based on an ever increasing variety and volume of information. (75) problems are also occurring in areas such as government, health care and education.

（75）是（）

A.Simple

B.Different

C.hard

D.Similar
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