数据库系统的并发控制主要方法是采用( )。
A．拒绝机制
B．改为串行机制
C．封锁机制
D．不加任何控制机制
参考答案：C
— Excuse me, what time is it now?
— Sorry, my watch ____. It _____ at the shop. [ ]
A. isn't working; is being repaired
B. doesn't work; is being repaired
C. isn't working; is repaired
D. doesn't work; is repaired
全过程造价咨询服务是运用工程造价专业技能对建设项目的组织实施进行（）的管理和服务。
A.设计
B.实施
C.策划
D.全过程
