Pirated music is a big challenge for Senegal's music industry.

VOA: standard.2009.08.27

So I think that it's true that the economy is difficult and there is big challenge in front of us.

所以我觉得，目前的经济形势真的很困难，我们面临着很大的挑战。

事业就是挑战 - SpeakingMax英语口语达人

And then we hand you 140,000 English words in the form of a big text file much like our aspiring pre-med students in recent months, and we challenge you to implement the fastest spellchecker possible.

然后我给你一个包含1万4千单词的超大文本,就跟前段时间那位,有抱负的医学预科班的学生一样,我想让你在最短时间内实现拼音检查。

哈佛公开课 - 计算机科学课程节选

"Rome" and "Big Love." Poul says his challenge was to balance the expectations audiences have for this genre.

VOA: standard.2010.04.30