"We have not shied away from raising the difficult problems that exist and stand in the way of the people of Africa realizing their potential.

VOA: standard.2009.08.16

Political tensions and conflict have made it difficult to deal with the problems.

VOA: special.2009.05.18

He says the student competitors showed they could solve difficult technological problems.

VOA: special.2009.04.24

Congress found it difficult to act on these problems.

VOA: special.2009.03.12

Some problems are difficult to solve.

VOA: special.2009.07.26

But the president reminded an enthusiastic crowd of Democrats that solving long-entrenched problems is a difficult process.

VOA: standard.2010.02.06

"The problem with that body of research is that it's difficult to interpret because obviously people with existing mental health problems use cigarettes to self-medicate."

VOA: standard.2010.06.15

It says these problems are made even more difficult by the sweltering summer heat.

VOA: standard.2009.07.03