【单选题】在 Visual FoxPro 6.0 中,若所建立索引的字段值不允许重复,并且一个表中可以创建多个,这种索引应该是( )
【简答题】合成胆固醇的基本原料和关键酶各是什么?胆固醇在体内可转变生成哪些重要物质?
【简答题】A company which owns another company is called __________ company.
【判断题】烟感探测器的电源口与外部电源连接时没有正负极之分。 ( )
【简答题】A company which owns another company is called a ______________.