The researchers point out that gene flow between crops and their wild relatives is common and difficult to contain.

VOA: special.2009.10.27

In Washington, Julianne Brienza notes that next year it will be more difficult to get donations for Capital Fringe.

VOA: special.2009.08.05

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 said later that he did so because he was finding it difficult to bring up the question of surrender.

VOA: special.2009.12.24

An extremely low body temperature can cause the heart to beat so slowly that a pulse may be difficult to find.

VOA: special.2009.12.30

He says the actively changing nature of the Internet makes it difficult to stay current in studying its effects.

VOA: special.2010.01.28

Today,the solution to the problem is so common that it is difficult to understand that there was a problem at all.

VOA: special.2010.07.14

Doctor Cawkwell told VOA that fibromyalgia is a very mysterious disease that has proved difficult to diagnose and treat.

VOA: special.2011.08.02

But he said he found it difficult to perform because Porgy has a bad leg and cannot walk.

VOA: special.2010.03.07

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

VOA: special.2009.04.14

And Howard Russell, an insect expert at Michigan State University, says once they get to the marching point, they are difficult to stop.

VOA: special.2009.01.27

The country had suffered a serious economic depression the year before, and jobs were difficult to find.

VOA: special.2009.05.28

And even if I had enough money, I knew that such diamonds are very difficult to find.

VOA: special.2009.07.18

"It was not difficult to agree between us that neither party is in favor of handing any more powers to the European Union."

VOA: special.2010.05.14