Although I had read the book assigned by
题型：选择题
问题：
Although I had read the book assigned by theprofessor several times,it didn't make
any _____ to me. [ ]
A. meaning
B. importance
C. sense
D. significance
题型：选择题
电路如图所示，电源电压不变，已知滑动变阻器的滑片P在中点c和端点b时，电灯的功率之比为9:4，电灯L的电阻与滑动变阻器R的电阻的比值（灯丝的电阻随温度的变化不计）：
A．2:1
B．1:2
C．4:1
D．1:4