风险成本一般可分为( )。 ①风险损失的实际成本;②风险损失的无形成本;③风险损失的预防或控制成本;④风险损失的有形成本;
A.①③④
B.②③④
C.①②④
D.①②③
参考答案:D
—I called you at school at half past eight last night, but nobody answered.
—Oh, I _ in my office at that time. [ ]
A. will work
B. worked
C. was working
D. had worked
病原菌检测中,不属于SPF级地鼠必须检测项目的是:()
A.金黄色葡萄球菌
B.嗜肺巴斯德杆菌
C.肺炎克雷伯杆菌
D.念珠状链杆菌