1.   Bert Bolin, the Swedish chairman of the panel, acknowledged that many uncertainties plague efforts to determine how serious the risk of climate change is.

2.   Despite some impressive improvements in academic performance, the school system is plagued by uncertainty.

3.   Mexican markets continued to be plagued by uncertainty over a United States aid package.

4.   Japan, the world leader in competitiveness for many years, is plagued by uncertainties.

5.   Japan, the world leader in competitiveness for many years, is still plagued by uncertainties.

6.   Medley said that because researchers must make assumptions in their computer models, predictions will continue to be plagued by uncertainty.

7.   New uncertainties plague UN investigators in Congo.

8.   Suddenly, Michelle Kwan is skating consistently and her top rivals are plagued by uncertainty.

9.   Uncertainty has plagued the markets for nearly three weeks, since the selection of the next president became mired in recounts and lawsuits in Florida.