You are working on a database that must be functioning 24 hours a day， 7 days a week. The database isconfigured in ARCHIVELOG mode. Which two options do you have for performing user-managed backups（）
A. You can perform consistent backups only.
B. You can perform a complete database backup without shutting down the database instance.
C. You can back up data files only when all data files have the same SCN recorded in the control file.
D. You can back up only those data files whose headers are frozen by using ALTER TABLESPACE BEGINBACKUP or ALTER DATABASE BEGIN BACKUP command
查看答案
ABO反定型是用已知的ABO血型红细胞作为试剂，利用__________鉴定血清中的__________。
Saltwater is typically provided to a refrigeration system to （）.
A. cool the expansion valve
B. prevent refrigerant superheating
C. condense the refrigerant gas
D. prevent motor overheating
在为专业消费者的服务中，推荐相关出版物，一定要面面俱到，把所有跟消费者需求有关的出版物都要推荐上，以免遗漏，这要求出版物发行员业务能力强，有一定的专业知识，掌握必要的专业出版物出版信息，比较了解每一位专业消费者的情况。
A. 正确
B. 错误
执法检查可以采取现场检查、重点抽查和普遍检查等多种形式。
A. 正确
B. 错误
微信支付 
支付宝支付