消弧线圈、干式电抗器、干式变压器感应耐压和局部放电测量，感应耐压：出厂试验值的（）。
A.60%
B.70%
C.80%
D.90%
参考答案：C
如果两个概念的外延完全重合，则这两个概念之间的关系是()。
A.同一关系
B.属种关系
C.交叉关系
D.矛盾关系
Recent studies have shown that most US graduates receive cash as gifts, though the amount
received ______ from person to person. [ ]
A. prefers
B. promotes
C. varies
D. suffers
