erase test feature

例句：

1. 1. He erased the last line of his essay before submitting it.
   他在提交论文之前擦掉了最后一行。
2. 2.The teacher asked us to erase all the mistakes from our papers.
   老师让我们把试卷上的所有错误都擦掉。
3. 3.After erasing the ink, he carefully wrote the next word on the paper.
   擦掉墨水后，他小心地在纸上写下下一个字。