单项选择题
A.2，3，4，1，6，5
B.3，2，4，1，6，5
C.3，2，6，4，1，5
D.4，2，3，1，5，6
多项选择题 ThedatabaseisrunninginNOARCHIVELOGmode.Adatafileislost.Whichtwoarevalidoptionsforrecover？（）
单项选择题 You received these error messages because the client cannot find the desired database： ORA-12198： TNS：could not path to destination ORA-12203： TNS：unable to connect to destination Which action would be appropriate in helping to resolve the errors？（）
单项选择题 Oracle Net Services is composed of several communication layers， known as a stack，which enables clients and database severs to share，modify，and manipulate data. Which reveals the correct architecture，in hierarchical order，of the client-side stack？（）