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

But for many of the world's poor, finding a good way to keep food cool is difficult.

VOA: special.2009.02.09

For example, celiac disease is difficult to identify because the signs of the disease are so common.

VOA: special.2009.04.14

For example,celiac disease is difficult to identify because the signs of the disease are so common.

VOA: special.2010.06.15

Sod can grow at times and in places where growing grass from seed is difficult.

VOA: special.2009.07.07

But it is difficult to read and judge a wave when it is near.

VOA: special.2009.03.17

Confirming Mister Muse's true age is difficult because birth documents are rare in Somalia.

VOA: special.2009.04.25

If using your voice is difficult, then you know what dysphonia is.

VOA: special.2009.09.02

Even today, it is difficult to walk or ride through the park.

VOA: special.2009.04.15

The F.A.O.says fish piracy is difficult especially for developing countries to fight.

VOA: special.2009.02.10

So it is difficult to see the animals in the sand.

VOA: special.2010.01.04

But it is difficult to put a price on troubled securities.

VOA: special.2009.01.30

It is difficult to tell exactly where the saying began.

VOA: special.2010.07.25

DiCaprio admits that talking about the film is difficult because revealing too much could spoil surprises that await the audience.

VOA: standard.2010.02.27