So, let's see this eraser actually never works very well so I'm just going to draw below it.

这个清除器不能很好地运行,我将在下面画出它。

哈佛公开课 - 计算机科学课程节选

It never works the first time if it's a big program.

如果它是个大程序的话基本上。

麻省理工公开课 - 计算机科学及编程导论课程节选