If you're stuck, if you're struggling, if you're not certain about something, please ask. We're not mind readers, we can't tell when you're struggling, other than sort of seeing the expression on your face, we need your help in identifying that.

如果你很差，如果你很纠结，如果你不确定某件事情，请问我们，我们不会读心术，我们没法儿看出来你们很纠结，除非能从你们的面部表情看出来，我们需要你们在这件事儿上的配合。

麻省理工公开课 - 计算机科学及编程导论课程节选