hich of the following RMAN structures can data from a datafile span?（） ["RMAN backup-set pieces spanning backup sets ","RMAN backup-set pieces within a given backup sets ","RMAN backups ","RMAN channels ","None of the above"]
变频器在安装接线时，尤其要注意是（）。 ["交流电源进线绝对不能接到变频器输出端","交流电源进线可以接到变频器输出端","交流电源进线应按正确相序接线","交流电源进线可不按正确相序接线"]
《水利水电工程施工质量检验与评定规程》SL176―2007（以下简称新规程）规定水利水电工程施工质量等级分为（）两级。 ["合格、优良","合格、不合格","合格、优秀","以上都不对"]
抗生素是如何杀菌和抑菌的？
Which two of statements are true？（） ["It is possible to synchronize static methods.","When a thread has yielded as a result of yield（）， it releases its locks.","When a thread is sleeping as a result of sleep（）， it releases its locks.","The Object.wait（） method can be invoked only from a synchronized context.","The Thread.sleep（） method can be invoked only from a synchronized context.","When the thread scheduler receives a notify（） request， and notifies a thread， that thread immediately releases its lock."]
百分表使用过程中应避免受到（）和振动。
