Consider alternatives: Expanding the electrical grid as is right now has been proven to be difficult and expensive.
Reconstructing the evolutionary relationships of Miocene apes has proven to be difficult for at least two reasons.
Translating that idea into policies that change state and local bureaucracies, however, has proven to be difficult everywhere, as it will probably be in Connecticut.
But it has proven to be difficult to make a profit from selling stuff online — a problem that is rarely acknowledged by the technology industry.
[C15.] Finding the Right Tax Advice Selecting an accountant and finding the best tax advice have proven to be difficult for some entrepreneurs.
To date, Kljestan has earned 34 caps for the United States but lately callups have proven to be difficult despite his club success.
This has proven to be difficult.
Even defining these aspects has proven to be difficult.
During several decades of privacy scholarship, defining privacy has proven to be difficult.
That said, turning the leading idea into a compelling argument has proven to be difficult.
However, the treatment of obesity has proven to be difficult, which makes prevention an important goal.
