If I want a copy of the string, I've got to whip out my week 1 skills of just iterating with a four loop from left to right and make copies of those characters.

我需要那个字符串的一个拷贝，我使用,第一周的技巧，从左到右做四次迭代,然后复制这4个字符。

哈佛公开课 - 计算机科学课程节选

You've probably heard it and use it many times.

你可能早就听说过，也使用过很多次了。

Let's 课堂 - SpeakingMax英语口语达人

But it's only an effective vaccine in the context where you have people who can go to the doctor's office, or to an urgent care, some kind of medical facility, three times, reliably, at a specified period of time.

但为了保证接种效果,人们必须亲自去诊疗室,或者在急诊室里,使用一些医学设施辅助接种,还需要接种三次,它只在一段时间内有效

耶鲁公开课 - 生物医学工程探索课程节选

So unlike Scratch where you pretty much had to say "repeat" ten times or whatever, or forever where it's just "forever" with for loops, -- can you actually specify a finite number of iterations -- and as I learned 15 years ago, finite is important.

所以不像Scratch，你大致上需要用,“repeat“10次或更多，或者需要不断地使用当它,是死循环时，你们能够指定出一个有限的迭代次数-,像我15年前学的，有穷的是重要的。

哈佛公开课 - 计算机科学课程节选