一定量的99mTc经过3个半衰期后放射性活度为原来的()
A.1/3
B.1/4
C.1/8
D.1/16
E.1/24
参考答案:C
There was _____to prevent the accident .
A something could do B anything we could do
C nothing we couldn’t do D nothing we could do
特别重大火灾是指造成30人以上死亡,或者100人以上重伤,或者一亿元以上直接财产损失的火灾()