作为一门独立学科的艺术学诞生于______。
A.17世纪末
B.18世纪末
C.19世纪末
D.20世纪末
参考答案:C
如图所示,电源电压为12V,R1=40Ω,开关S断开时,电流表的示数为0.2A,求:
(1)R2的阻值。
(2)开关S闭合后,电流表的示数。
The teacher demanded that the exam _____ before eleven.
A.must finish
B.would be finished
C.be finished
D.must be finished