13. ( ) is indicated by the height of a wave within a given period of time. A. Amplitude B. Frequency C. Analog signals D. Digital signals ...

7. In a ( ) network, all microcomputers and other communications devices are connected to a central hub, such as a file server or host computer, usually via (UTP). A. bus B. star C. tree D. ring ...

8. Information is summarized data or manipulated data.( ) A. 错误 B. 正确 ...

2. Memory also called main memory, primary storage, RAM, is an internal storage area in the computer, where data and programs designed for immediate processing are held.( ) A. 错误 B. 正确 ...

3. ( ) stands for Random Access Memory.It is the main location for holding programs and data that the CPU is presently processing. A. RAM B. ROM C. input devices D. memory ...

10. 删除索引的SQL语句是（）。 A. drop index B. create index C. use_help index D. 以上都不对 ...

4. 要删除视图myviewview，可以使用（）语句。 A. DROP database myviewview B. DROP TABLE myviewview C. DROP INDEX myviewview D. DROP VIEW myviewview ...

8. 索引是与表（或视图）关联的页的集合，用于加速从表中检索数据。 A. 错误 B. 正确 ...

3. 混合验证模式可以允许以SQL Server身份验证模式或者Windows身份验证模式来进行验证。 A. 错误 B. 正确 ...

7. 在select查询语句中的like 'JS_'表示（）的字符串。 A. 长度为3的以“JS”开头 B. 长度为2的以“JS”开头 C. 任意长度的以“JS”开头 D. 长度为4的以“JS”开头第三个字符为“_” ...