A white chalk chalks white on a black blackboard.一根白色的粉笔在黑色的黑板上写白字.His steed was by chalks the best.他的马是最好的.The prisoner has walked his chalks , and is off to London.那囚犯逃走了, 逃到伦敦去了....drawing a small picture with coloure...
屋顶的两面斜面都有破瓦片.On both slopes of the roof there are broken tiles.伽利略让小金属球从斜面滚下.Galileo rolled small metal balls down the incline.图3.21画出了平行于斜面的、相互保持平衡的几个力.Figure 3.21 shows the forces parallel to the plane that are respons...