Gee, have you ever wondered how they know the composition of stars that are light-years away?

嘿！你曾经是否想过,他们是怎么知道那些离我们好几光年远的,星星的位置的？

麻省理工公开课 - 固态化学导论课程节选

So, have you ever liked somebody or disliked them and not known why?

例如，你是否曾经毫无理由地,喜欢或厌恶过某个人？

耶鲁公开课 - 心理学导论课程节选