The removable stoppers allow students to fill them with rice or sand.
The removable stoppers allow students to fill them with rice or sand.
学生可通过立方体底部的洞口注入泥沙或食米，让他们学习形状、大小和体积等概念。
The removable stoppers allow students to fill them with rice or sand.
学生可通过立方体底部的洞口注入泥沙或食米，让他们学习形状、大小和体积等概念。