Published methods should be used with __________.
A. acknowledgement
B. result
C. reason
D. justification
低通滤波电路()。
A. 无截止频率
B. 具有上限和下限截止频率
C. 具有上限截止频率
D. 具有下限截止频率
Vulnerability is characteristic of a system without _________ a specified class of security breaches would not be possible.
A. which
B. that
C. it
D. this
地质学的研究对象固体地球哪些部分?
A. 地核
B. 地幔
C. 地壳和岩石圈
D. 软流层
E. C