____ ____ the level of the sea risen a little these years?
从南极到北极,纬线的度数变化规律是( )
在测定“小灯泡电功率”的实验中,电源电压为4.5V,小灯泡额定电压为2.5V、电阻约为10Ω。
——Must I work out the problem right now? ——Yes, you _______. It's very serious.