题型:名词解释 飞机在飞行时受到的空气阻力与速率的平方成正比.若飞机以速率v匀速飞行时,发动机的功率为P,则当飞机以速率nv匀速飞行时,发动机的功率为( )A.nPB.2nPC.n2PD.n3P 查看答案
题型:名词解释 The photographer needs to charge up the digital camera every day as the battery quickly.A.shuts upB.ends upC.runs outD.turns out 查看答案