And then I could put a couple of plates and I could raster the beam so that when I am looking here,the beam goes back and forth about 80 times a second.

然后我放了两个感光片,我可以检测到光束所以,当我观察时,电子束以每秒80次的速度来来回回了。

麻省理工公开课 - 固态化学导论课程节选

You throw out little slips of paper and they take turns going back and forth.

你如果将竞价写在纸上，他们会来来回回地传阅。

充满乐趣 - SpeakingMax英语口语达人

The sense of going back and forth, no one of us on top, not correspondent in a vertical way, how things going down there.

这种来来回回的感觉，没有人是在高处，也没人在低处。

普林斯顿公开课 - 人性课程节选

The cookies were going back and forth and back and forth and the hearts up and down, well, this thing that we had that called a loop last week with a forever block with a statement inside of it is simply gonna look a little something like this.

这些饼干人来来回回的移动,还有这些爱心们上上下下地漂浮,都用到我们上周提到过的循环结构,当然还有个声明在里面，就有点像屏幕上,显示的这样。

哈佛公开课 - 计算机科学课程节选

People jog and bike up and down there.

人们在那儿来来回回地慢跑、骑自行车。

我的爱好是读书 - SpeakingMax英语口语达人