退格键

例句：

1. 1. I need to delete the last paragraph of my email.
   我需要删除我的电子邮件的最后一段。
2. 2. The teacher instructed us to backspace our answers before submitting them.
   老师指示我们提交答案前要回退。
3. 3.After editing the document, I decided to backspace and start over.
   编辑完文档后，我决定回退并重新开始。