In modern computational mathematics and engineering, the obstacle problems are not extremely difficult to solve numerically any more, as shown in numerous publications; see [8 14], for example.
After yesterday's rulings, Vice President Al Gore's lawyers face new obstacles in what was already an extremely difficult fight to win the White House through a court-ordered recount.
Unfortunately, there are a wide variety of obstacles to repeat donation and new donors are extremely difficult to retain.
In Africa, social and cultural obstacles – as well as government policies – make it extremely difficult for WSW to speak to health practitioners about sex, and to access dental dams and other means of safe sex.
But, after ten months, three days and an extremely difficult labor and aftermath, my little girl arrived, making each obstacle and every pain worth it.
However, the process of developing and implementing business risk audits was extremely difficult and may have run up against a number of unforeseen and unmanaged obstacles, particularly in regards to the existing rituals of the traditional audit.
The problem is extremely difficult, water being a medium quite different from air, and much work will be needed to overcome the obstacles.
Hedging is extremely difficult.
"It was extremely difficult.
