当线圈中的电流()时,线圈两端产生自感电动势。
A、变化时
B、不变时
C、很大时
D、很小时
参考答案:A
All the clerks went home _______ Mr. Wang, for he had to finish his work.
[ ]
A. except
B. besides
C. without
地黄饮子的功用为()
A.滋阴补肾,开窍化痰
B.补肾温阳,开窍化痰
C.滋肾阴,补肾阳,开窍安神
D.滋肾阴,补肾阳,化痰止咳
E.滋肾阴、补肾阳,开窍化痰