class board

例句：

1. 1. The teacher uses a blackboard to explain the math problems.
   老师用黑板来解释数学问题。
2. 2. The students are sitting in their seats, waiting for the class to begin.
   学生们坐在座位上，等待上课开始。
3. 3. The teacher writes important information on the whiteboard for easy reference.
   老师在白板上写下重要信息以便参考。