Once the reliance on air strikes proves unproductive, what next: ground troops?
But his first two attempts on her behalf proved unproductive.
Mediation efforts led by Ugandan President Yoweri Museveni have so far proved unproductive.
Though his attempts proved unproductive, they stimulated him to explore the use of radioactive isotopes as tracers.
Christopher A. Viehbacher, Sanofi's chief executive, said on Monday that while he had met with Henri A. Termeer, his counterpart at Genzyme, for several hours last month, the talks proved unproductive.
As a result, they may be tempted to hide their mistakes, or even worse, continue down paths that have proven unproductive.
Since the days of the Soviet Union, the Kremlin has been eager to exploit giant nonporous rock fields in western Siberia, but the fields have proved unproductive using conventional vertical drilling techniques.
The talks with Glasgow's Old Firm proved unproductive, Carter recalled, and the self-styled elite of English clubs – intent upon exerting greater influence and enjoying revenue to match – approached the Football Association about their ideas.
Frelimo's agricultural undertakings proved unproductive and unmanageable, however, and, in combination with the flight of South Asian merchants and the instability caused by guerrilla warfare, much of the country's agricultural production, commerce, and distribution system collapsed.
These and other pressures on traditional culture were clear abrogations of tribal sovereignty, but tribes from the Southeast culture area saw just as clearly that fighting them head-on would prove unproductive.
Raising rates could prove unproductive for tax receipts going forward.
