A:①③④
B:②③④
C:①②④
D:①②③
一物体在光滑斜面上初速度为0,从斜面顶端匀加速下滑,当下滑距离为L时,速度为V,那么速度为2V时,物体沿斜面下滑的距离是( )
下列关于浮力的说法中正确的是( )
-- Anna, could you lend me this book, please?
-- I'm sorry. I it for only two days, and I haven't finished it yet.
将马铃薯的块茎切成小块来种植时,每一小块都要带有芽眼。