这个圆筒的体积有多少?What's the volume of this cylinder?通常平动和转动同时发生, 例如,圆筒的滚动.Often translation and rotation occur simultaneously, as in the case of a rolling drum.空气的分子会撞击圆筒的整个筒壁和上下两端.The molecules of air would bombard all s...
橡皮艇航行时吃水很深.The rib rides low in the water.那个男人用橡皮艇来装雨水.The men collected rainwater in rubber dinghy.他们用橡皮艇蓄积雨水.The men collected rain - water in the rubber dinghy....