Sentence examples for has proven extremely difficult from inspiring English sources
Growing such exposure organically has proven extremely difficult and costly for many asset managers.
During the past decade methods have become available that can identify specific genes but it has proven extremely difficult to find these genes; the most likely reason is that many genes are involved and each gene has a very small effect.
Though the mastery of such systems is highly desirable, it has proven extremely difficult in the past, with several failures.
Because identifying pinholes, should they exist, in thicker films has proven extremely difficult, 10 nm films were applied to investigate the nature of pinholes in Al2O3 ALD films.
As Nagel (2002, 34) admits, "it has proven extremely difficult to account for such a basic, individualized value such that it becomes morally intelligible".
In spite of these advances, it has proven extremely difficult to simultaneously maintain the phenotypes of hepatocytes and LSECs in vitro.
A confidential Foreign Office briefing in 2007 mendaciously concluded that "it has proved extremely difficult to disentangle the truth" about the Armenian genocide.
The deletion of internet data logs in the ordinary course of business means that tracing historic edits to a particular department, building or individual has proved extremely difficult.
A 35-mile stretch of the Kalamazoo River remains closed and cleanup has proved extremely difficult, running over budget and past deadlines set by the E.P.A. Estimates of cleanup costs have run well over $500 million.
It is a substance that has proved extremely difficult to detect, but baseball will now try, moving ahead of other leagues like the N.F.L. There, the players have backed away from the H.G.H. test, raising various reservations.
