滑道
参考答案：斜面上供船舶上墩下水的专用轨道称为滑道。
一个正方形的周长是20厘米，这个正方形的边长是______厘米．
“Attention, please. Whoever can answer one of my questions _____ receive a prize,” the teacher said in class.
A．might
B．would
C．should
D．shall
