网络图的基本构成要素是（）。 ["始点、终点、箭线","主作业、虚作业、关键作业","时间参数、关键路线、紧前紧后关系","作业、节点、路线"]
Which command will retrieve /unix and dump from the dump device？（） ["snap -R","snap -D","snap -U","snap -N"]
未取消辅修货车厂、段修时，三通阀质量保证期限为（）。 ["6个月","1年","1个辅修期","1个段修期"]
提取坏帐准备所依据的会计核算的一般原则是（）。 ["谨慎性原则","相关性原则","配比原则","一致性原则"]
You are a database developer. You plan to design a database solution byusing SQL Server 2008. You are creating adataba seto support the office manager. Your database model has the following structure. The database design has the following business requirements: An employee can be assigned more than one task. Upon completion, thetask is deleted. When a task is deleted, the associated assignment is deleted. When an employee is nolonger available tocomple tea task, theemployee link to the assignment is replaced with a NULL value. You need to implement the business requirements to maintain data integrity. What should you do?（） ["Create DDL INSERT triggers on the Employee. Task and Assignment entities.","Create CHECK constraints on the Task ID and Employee ID attributes in the Assignment entity.","Create Foreign Keys constraints on the Task ID and EmployeeID attributes in the Assignment entity. Reference the Task and Employee entities respectively. Specify the appropriate On Delete action.","Create Foreign Keys constraints on the Task ID and Employee ID attributes in theTask and Employeeentities respectively. Reference the Assignment entity, and specify the appropriate On Delete action."]
顾泠沅《课堂视野中的教师及其指导者》中指出：学生要靠每位学生的（）。这种自觉有两个起点――自读（）和自做（），教学要摆脱灌输式，非得凸现这两个起点不可。
