The program employs locals as field officers for a period of three years.

VOA: standard.2010.07.01

If I can run the gel for some period of time, run the electrical field, spread it out.

我将凝胶通电一段时间后,在电场作用下,就会分散开来

耶鲁公开课 - 生物医学工程探索课程节选

That is a maximum If you are sharing your time and energy during this period on Tuesday afternoons, or the arch-field don't work so think carefully about that.

让大家充分发挥自己的能力,如果每周二下午这段时间,你都有时间，精力也很充沛，就可以来上这门课，不过这样你就没时间参加实践活动了,所以请仔细考虑吧。

麻省理工公开课 - 电影哲学课程节选

At the same time, I do mean to give you some sense of the period in which they're writing, some sense of modernism as a field, as one of the richest fields in English language writing.

同时，我也会给你们提供一些背景知识,来了解作者创作的年代，以及现代主义的思想领域，就其作为英语文学创作最丰富的领域之一而言。

耶鲁公开课 - 现代诗歌课程节选