- Part of the challenge is speed, too, how quickly you can get these answers in terms of getting them in on time.

部分困难也会来自于速度，你多快能做出答案,能否在规定的时间做完。

麻省理工公开课 - 化学原理课程节选

So the challenge thing comes back to the instruction of designer: what are you for on this access?

这样，教育设计者,又重新面临着挑战：,你会支持这项技术吗？

麻省理工公开课 - 媒体、教育、市场课程节选

And the challenge for scheduling is to pick the things that you want the president to be working on and the president wants to be focusing on proactively rather than just reacting to whatever the crisis on the day was.

安排日程的难处在于,选择事情,选择你要让总统去做,选择总统需要积极投入,而不仅仅是消极回应的,每天发生的大事情。

普林斯顿公开课 - 国际座谈会课程节选