"The job market is still very difficult. We are seeing layoffs continue, not at the heavy pace we saw at the beginning of the year, but they certainly have not abated,"

VOA: standard.2009.08.05

And scientists have been working on this for years and there's been progress, but it's still a very difficult challenge.

科学家们对此已经研究很久了,并取得了进展,但仍有很大挑战

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选