A:that; that; possible
B:which; that; impossible
C:which; what; possible
D:what; which; possible
使唐朝由盛转衰的标志性事件是( )
下面的电路中,开关S闭合时,电流表A1与A的示数如图甲、乙所示,则电流表A2的示数为( )
如图,在Rt△ABC中,∠C=90°,AB=2BC,则sinB的值为____