The challenge is to pick out oil from other dark spots, such as shadows made by clouds or patches of seaweed.

VOA: standard.2010.07.05

Working in so many different genres, Williams says his daily challenge is coming up with the right sound for a show,movie,or album.

VOA: standard.2010.07.20

Sitting next to Mr.Meles at the signing ceremony were three top members of the old Coalition for Unity and Democracy,or CUD which mounted a powerful challenge to Mr.Meles party in the 2005 parliamentary vote.

VOA: standard.2009.11.01

"The EPRDF has discussed with parties that seem to approve or endorse its lines, not the serious parties that do challenge the EPRDF and do have serious issues about the political space in the country,"

VOA: standard.2009.11.01