Why not __________ your teacher for help when you can't finish the story by yourself?
A:to ask, write
B:to ask; to write
C:ask; writing
D:asking; to write
基因型为YyRReeDD的个体,四对基因分别位于四对同源染色体上,这样的个体自交后代的表现型的比例接近于( )
车轮要做成圆形,实际上就是根据圆的特征( )
A.电压表(0~5V,内阻约10kΩ)
B.电压表(0~10V,内阻约20kΩ)
C.电流表(0~0.3A,内阻约1Ω)
D.电流表(0~0.6A,内阻约0.4Ω)
E.滑动变阻器(10Ω,2A)
F.学生电源(直流6V),还有开关导线