多项选择题 The CURSOR_SHARING parameter is set to SIMILAR at the instance level and you issue these SELECT statements in the order shown below：   SELECT * FROM employees WHERE department_id=50；  SELECT * FROM employees WHERE department_id=70； There is an index on the DEPARTMENT ID column of the 1，000，000 row EMPLOYEES table. Ninety percent of the employees are part of the DEPARTMENT_ID 50. In which two scenarios will Oracle9i share the corresponding cursors for the two statements？（）

单项选择题 ThedirecthandoffconnectionmethodtoanOracle9iSharedServerinvolvesfewermessagesthaninpreviousreleasesofthemultithreadedarchitecture.Whichtypeofmessagehasbeeneliminated？（）

多项选择题 WhichthreeresourceplanparametersareusedtoenableAutomaticConsumerGroupSwitchingtoestimatejobexecutiontimesautomatically，andtoperformaswitchtoalowpriorityconsumergroupbeforetheyareinitiated？（）