What is the result？（） Compilation fails.。 pi is bigger than 3.。 An exception occurs at runtime.。 pi is bigger than 3. Have a nice day.。 pi is not bigger than 3. Have a nice day.。
表面粗糙度参数
Which three statements are true about Automatic Workload Repository (AWR)?（） All AWR tables belong to the SYSTEM schema.。 The AWR data is stored in memory and in the database.。 The snapshots collected by AWR are used by the self-tuning components in the database。 AWR computes time model statistics based on time usage for activities, which are displayed in the v$SYS time model and V$SESS_TIME_MODEL views.。 AWR contains system wide tracing and logging information.。
电气设备着火时，应使用（）灭火。 泡沫灭火器。 干式灭火器。 自来水。
论述离心泵振动的主要原因。
低温绝热气瓶。每（）年检验一次。
