Good question, so there is this little reading head kind of like in an old phonograph player that does move back and forth and in and out depending on the implementation.

好问题，这就像,老留声机里的小读头,它通过来回移动,来完成不同的操作。

哈佛公开课 - 计算机科学课程节选

Yeah, over the past 2 years I've been back and forth in Brazil.

是，过去两年我来来回回去了巴西好多次。

我来自阿拉斯加 - SpeakingMax英语口语达人

You see a bleep going across the screen to indicate that they've got their finger on the pulse of what's happening, or you see it in TV shows like ER.

你们看到一个亮点在屏幕上来回跳动,来显示病人脉搏的,跳动情况,就像在急诊室的故事,这类电视中看到的那样

耶鲁公开课 - 生物医学工程探索课程节选