登记系统操作员具有()的权限。
A.登记
B.创建
C.查询
D.维护
参考答案:A, C
He made another wonderful discovery, ________ of great importance to science. [ ]
A. which I think is
B. which I think it is
C. which I think it
D. I think it is
采样精密度的计算公式为()(上杠在S上方)。(高级)