放射防护中的ALARA原则是（）
A、放射实践的正当化
B、放射防护的最优化
C、个人剂量限值
D、保护周围环境的最低值
参考答案：B
--- I ______ so busily recently that I ______ no time to help you with your math.
--- That’s OK. I can manage it by myself.
A．have been working; have
B．have worked; had
C．am working; will have
D．had been working; had had
根据分公司旧件回收的相关规定，下列哪些配件应该给与回收（）。
A.易损配件
B.高价值配件
C.可换可不换的配件
D.中支公司自行确定回收的配件
