scratch board

例句：

1. 1.The teacher used a scratch board to explain the math problem.
   老师用刮板板来解释数学问题。
2. 2. She used a scratch board to draw her designs on paper.
   她用刮板板在纸上画她的设计。
3. 3.The students used the scratch board to practice their drawing skills.
   学生们用刮板板练习他们的绘画技巧。