So where does this constraint, you may think it's a fairly minimal constraint, but where does it come from?

你可能觉得这些制约相当微小，但它从何而来呢？

耶鲁公开课 - 公正课程节选

Where do you get your inspiration for writing?

你的写作灵感从何而来？

灵感从何处来 - SpeakingMax英语口语达人