【简答题】3 卡介苗是用人工方法使_______失去毒力制成的生物制品,可用于预防_____病。
【单选题】射线辐照红细胞之后,对有核细胞的杀死率为
【判断题】气门传动组由气门、气门导管、气门弹簧、弹簧座及气门锁片等组成 。( )
【单选题】下列属于医药宏观市场营销环境的是( )。
【单选题】关于短路计算中的,下面描述 正确 的是: ( )
B.
标幺值短路计算结果可能和欧姆法短路计算结果不同。
C.
标幺值法计算短路电流时,基准容量一定要取100MVA。
【单选题】When the old man ______ to walk back to his house, the sun itself behind the mountain.
A.
started; had already hidden
B.
had started ;had already hidden
C.
had started; was hiding
【单选题】It _____ everyone to hear all of the villagers behind the mountain were killed in the flood. [ ]