If that proves impossible, German diplomats indicate they might consider backing European sanctions which the U.S. wants.

NPR: German Chancellor Merkel to Visit Bush

If that proves impossible then governments will have to step in despite the unpopularity of being seen to further bail out banks.

BBC: Europe's 'big bazooka'

If, after the process of considering amendments, it proves impossible to reach agreement on a non-financial bill, then the bill may be lost.

BBC: Passage through the other House

The situation is further complicated by the fact that it often proves impossible to identify which particular condition a person is suffering from.

BBC: Change your life, not your keyboard

Officials are ready for a summit that drags into the weekend or one that breaks up much earlier if a deal proves impossible.

BBC: David Cameron and the EU budget meeting

If money simply proves impossible, John believes that Jamie might start at a less-expensive school for a year or two, before transferring to her dream college.

WSJ: Should Cost Affect Where Our Daughter Applies to College?

But the fact that Chelsea, Saturday's vanquished opponent, is on its way to achieving it, proves not just that it isn't impossible, but that City may well be on the right track.

WSJ: English Premier League: Manchester City, Soccer's New New Money