Clara Maass died six days after she was bitten for the seventh time.

VOA: special.2010.05.18

And fixed versus variable speaks to whether you give a reward on a fixed schedule, every fifth time, or variable, sometimes on the third time, sometimes on the seventh time, and so on.

固定与变化则是相对于,你是否根据固定时程给予奖励而言的，每五次就给予奖励，或者是变化的，有时候在第三次上给予奖励，有时候则在第七次上给予奖励。

耶鲁公开课 - 心理学导论课程节选

So, now I hope you have in your mind a picture of the way the Greek world had expanded by the time this wave of colonization was complete--pretty complete, sometime in the seventh century B.C.

希望现在你脑海中有一幅,那时候希腊世界扩张的地图,在公元前七世纪的某一阶段,形成了一个完整的殖民浪潮,相当完整

耶鲁公开课 - 古希腊历史简介课程节选