But the professor says it is difficult to find enough feathers from a single dinosaur to recreate all its colors.
VOA: special.2010.03.16
He says the actively changing nature of the Internet makes it difficult to stay current in studying its effects.
VOA: special.2010.01.28
Industry leaders, meeting this week in Malaysia, were told that their industry faces its most difficult situation ever.
VOA: special.2009.06.13
The recovery of the Stardust capsule was difficult because of its high reentry speed.
VOA: special.2009.09.30
But the timing of its opening in January has been difficult.
VOA: special.2010.03.31
Crystal says the dynamic nature of the Internet makes it difficult for comprehensive analysis of its effects to stay up-to-date.
VOA: standard.2010.01.16
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