21.   There is uncertainty, too, about the corresponding close back rounded vowels.

22.   Already there is some uncertainty about whether this new technology will produce a wider selection or simply digital slush.

23.   Although the drug cocktails are helping tens of thousands of infected people live longer and better, there is uncertainty about their long-term safety.

24.   Although the Horns are confident in their new scheme, there is the uncertainty of what UCLA will do.

25.   Although no one suggests that Bush is in any immediate danger of losing his front-runner status, there are enough uncertainties to give his rivals hope.

26.   Although his appointments may offer clues, there is real uncertainty as to where Putin intends to take Russia next.

27.   Although there is uncertainty about his future position, there are no doubts about his ability to compete at this level.

28.   Among the difficulties is the uncertainty over how to approach companies with offices in or near ground zero of the terrorist attacks, Day added.

29.   An earlier experiment at Fermilab found a still larger value, near the upper end of the predictions, though once again the uncertainties were substantial.

30.   An even bigger uncertainty is the question of how rapid climate change would affect relationships among species, and how those relationships in turn might affect migration patterns.