放射性废物,其活度浓度或活度()国家审管部门规定的清洁解控水平。
A.等于
B.大于
C.小于等于
D.不等于
参考答案:B
--- Did your classmates have a good time in the Disneyland last weekend?
---Yes. They enjoyed _________ very much.
A.themselves
B.yourselves
C.ourselves
D.himself
救生索的要求是()。
A.长20m
B.长30m
C.抗拉强度2000kg
D.抗拉强度3000kg