—What will the phone ?
—The same as you said, eight hundred dollars each.
A:spend
B:cost
C:pay
D:afford
则该植物一年生长在30,40)内的频率是( )
A good listener takes part in the conversation, ______ ideas and raising questions to keep the talk flowing.
如图,将边长为a的正六边形A1A2A3A4A5A6在直线l上由图1的位置按顺时针方向向右作无滑动滚动,当A1第一次滚动到图2位置时,顶点A1所经过的路径的长为( )