下面哪句话比较准确地定义了Delphi（） ["面向对象的可视化的开发环境","多媒体制作工具","数据库的客户端开发工具","高级编程语言"]
管道封堵作业时，通过（）来操作夹板阀。 ["气动","液压或手动","电动","液动"]
You are working on a very large database. You had performed a binary backup of the control file a month ago. After this you added a few tablespaces， and dropped a couple of tablespaces. This morning， due to hardware failure， you lost all your control files. How would you recover the database from this situation？（） ["A","B","C","D","E"]
采用一台三相三柱式电压互感器，接成Y----Y形接线，该方式能进行（） ["相对地电压的测量","相间电压的测量","电网运行中的负荷电流监视"]
On Monday， you dropped the DEPT table from your schema and then you re-created the DEPT table in your schema. On Wednesday， you have a requirement to restore the DEPT table from the recycle bin. Which statement is correct？（） [" You cannot restore the DEPT table by using the Oracle Flashback Drop feature because a table with the name DEPT already exists in your schema."," You can restore the DEPT table by using the Oracle Flashback Drop feature， provided you use the RENAME TO clause."," You cannot restore the DEPT table by using the Oracle Flashback Drop feature because the contents of the recycle bin are purged every 12 hours by default."," You can restore the DEPT table by using the Oracle Flashback Drop feature and a system-generated name will be assigned to the restored table."]
轴上零件作周向固定的目的：是为了保证（）转矩时，轴上零件与轴之间不产生（）。
