It was nice because it wasn't just, "Okay, Let's write a story" or "Let's do a research about the animal" or "Let's do a poem about fish".

说它出色，因为孩子们这样做，不是因为老师要求“,或布置的任务“,或学校强制。

麻省理工公开课 - 媒体、教育、市场课程节选

Right. Related to that: attendance here is obviously not mandatory.

对了，关于那个事儿：,出勤明显不是强制要求的。

麻省理工公开课 - 计算机科学及编程导论课程节选

Does science require that we believe in the physicalist view or not?

科学有没有强制要求,我们接受物理主义的观点

耶鲁公开课 - 死亡课程节选

These are completely optional, not required for the course, so there's no obligation for you guys to get involved in these things, but I'll mention these things as we go along in case anybody would like to get involved in working with professors or graduate students.

这些都是自愿选择的,而不是课程要求,所以并不强制你们都参加,但随着课程的进行,我还会不断提及,便于任何感兴趣的同学,能够与教授或研究生一同参与研究

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选