His years of hard work paid off.

VOA: special.2010.01.13

It's great idea with a lot of hard work and then you work at it for year, two years, three years, four years, five years, six years, seven years, eight, nine, 10.

勤奋的工作，一年两年，三年,有或者更多，甚至10年，是很好的想法。

斯坦福公开课 - 微软CEO-Steve.Ballmer谈科技的未来课程节选

There's been a lot of work done on these over the years, but in fact, it's pretty hard to invent a good hash function. So my advice to you is, if you want to use something was a hash, go to a library. Look up a good hash function.

已经做过了很多的尝试和努力,但是事实是，很难发明出一个好的哈希函数,所以我给你们的建议是,如果你们想使用哈希功能,到函数库中查找一个好的哈希函数。

麻省理工公开课 - 计算机科学及编程导论课程节选

He called the document a great achievement, after years of hard work.

VOA: standard.2009.10.23

One reason it's been harder to identify stem cells is that they're so rare; the other reason is that it's hard to identify the characteristics of them and it's taken many years to work this out.

干细胞难以识别的原因之一是,这些细胞很少,另一个原因就是,干细胞的特征性蛋白难以识别,我们花了好多年去解决这个问题

耶鲁公开课 - 生物医学工程探索课程节选