roll-over board

例句：

1. 1. The teacher askedthe students to roll over their papers andanswer the questions on the board.
   老师要求学生们将试卷翻过来，在黑板上回答问题。
2. 2. The studentused a turn-over boardto demonstrate how to solve the problem.
   学生使用翻页板来演示如何解决这个问题。
3. 3.The engineer designed a flip-over boardthat could be easily folded and stored.
   工程师设计了一种可以折叠和存储的翻页板。