双重绝缘是指工作绝缘和()
A.基本绝缘
B.保护绝缘
C.总体绝缘
D.加强绝缘
参考答案:B
司马迁,司马昭,司马光,哪一个是汉朝人
A huge copy of “Zhang Zeduan’s Qingming Festival at the Riverside” in the Shanghai Expo brings a grand _________of national treasures and cultures to the Expo table.
A.chart
B.feast
C.impression
D.influence