Also, if you look at prison movies, sometimes the way that the guards torture the prisoners is to get them to dig a hole, and when the prisoner is finished, they ask him to fill the hole back up and then dig again.
或者，如果你看过监狱题材的电影的话， 有时看守是这样折磨犯人的 先让他们去挖洞 当他们挖好洞之后， 又叫他们把那个洞填上，然后再重新挖。