You decided to increase the value for the SHARED_SERVERS parameter by using the following command： SQL> ALTER SYSTEM SET SHARED_SERVERS=3 SCOPE=？； Which three values can be specified for the SCOPE clause？（） ALL。 PFILE。 BOTH。 NONE。 SPFILE。 MEMORY。 INSTANCE。 DATABASE。
浇筑式沥青混凝土的拌和、运输、摊铺、养护等与一般沥青混凝土没有什么区别，因此，其工程造价的计算完全可以采用沥青混凝土预算定额计算
如果在窗体上设计一个主菜单，首先要建立（）对象。
耶克斯－多德森定律描述了学习动机与学习效果之间的关系根据该定律，以下描述正确的是（） 任务难度中等时，最佳动机激活水平也中等。 动机水平越高，学习效果越好。 任务较难时，最佳动机激起水平较低。 任务较容易时，最佳动机激活水平较高。
You want to track and store all transactional changes to a table over its lifetime. To accomplish this task， you enabled Flashback Data Archive with the retention of 5 years. After some time， the business requirement changed and you were asked to change the retention from 5 years to 3 years. To accomplish this， you issued the following command： ALTER FLASHBACK ARCHIVE fla1 MODIFY RETENTION 3 YEAR； What is the implication of this command？（） The command produces an error because the retention time cannot be reduced.。 All historical data is retained but the subsequent flashback data archives are maintained for only three years.。 All historical data is purged and the new flashback data archives are maintained for three years.。 All historical data older than three years is purged from the flashback archive FLA1.。
高压不停输施工作业时，在开孔设备安装后，阀门装置的试验压力一般为（）
