[多选]

You notice a high number of waits for the db file scattered read and db file sequential read events in the recent Automatic Database Diagnostic Monitor (ADDM) report. After further investigation, you find that queries are performing too many full table scans and indexes are not being used even though the filter columns are indexed.
Identify three possible reasons for this.（）

在气瓶上使用警示标签可以提供（）信息。 瓶装气体名称及化学分子式；。 混合气体主要成份的名称和化学分子式；。 瓶装气体的充装方法；。 瓶装气体应采取预防措施的附加说明。 老舍的最后一部长篇小说是（） 《骆驼祥子》。 《四世同堂》。 《龙须沟》。 《正红旗下》。 西方的“博爱”可以说是先秦（）思想的最好对译，它还脱去了西方“博爱”的宗教色彩。 A PL/SQL procedure queries only those columns of a redefined table that were unchanged by the online table redefinition.  What happens to the PL/SQL procedure after the online table redefinition？（）  It remains valid.。  It becomes invalid for all options of online table redefinition but automatically gets revalidated the next time it is used.。  It becomes invalid for all options of online table redefinition and is automatically recompiled during online redefinition of the table.。  It becomes invalid only if the storage parameters have been modified and it automatically gets  revalidated the next time it is used.。 简要叙述机器设备评估的基本步骤。

You notice a high number of waits for the db file scattered read and db file sequential read events in the recent Automatic Database Diagnostic Monitor (ADDM) report. After further investigation, you find that queries are performing too many full table scans and indexes are not being used even though the filter columns are indexed.
Identify three possible reasons for this.（）