"Erase the blackboard" is the phrase used to describe the act of cleaning a blackboard. The phrase comes from the practice of using a chalkboard or blackboard as a writing surface in classrooms. The blackboard is typically cleaned with an eraser after the lesson is finished, in order to prepare it for the next class.
Here are some example sentences:
Can you please erase the blackboard before we start the next lesson?
The teacher asked the student to erase the blackboard after class was over.
The janitor was responsible for erasing the blackboards in the school every evening.
翻译:
下课前能请你擦黑板吗？
老师让学生课后擦黑板
清洁工每天晚上都要擦学校里的黑板。