A:电流一定相等
B:电压一定相等
C:电阻一定相等
D:电流、电压和通电时间的乘积一定相等
如图,在△ABC中,AD⊥BC于点D,BD=CD,若BC=6,AD=5,则图中阴影部分的面积为 ( )
He looked calm, but a____, he was very nervous.