41.   The answer proposed by the four was the supernova, in which a giant star collapses to extreme density, then cataclysmically rebounds.

42.   The aluminum and stainless steel works are on tracks so that they can be opened in the middle of a lobby or collapsed to become wall reliefs.

43.   The internally displaced should get aid when countries request it, or when a state has collapsed to the point where no one can give permission.

44.   The once-soaring stock price collapsed to virtually zero, and within weeks the company was forced to file the biggest bankruptcy case in U.S. history.

45.   The roof and four floors collapsed to the bottom of the building, and Brockman said the smouldering debris within the walls is at least several feet deep.

46.   The roof on the passenger side was collapsed to within two feet of the floor.

47.   The Trade Center towers collapsed to the ground around and on top of the downed jets.

48.   Then he collapsed to the ground, exhausted.

49.   This gas could collapse to the surface of the planet under enough pressure to become an opaque, heat-retaining blanket, he said.

50.   This, they wrote, suggests that the West Antarctic ice sheet had collapsed to some degree at least once within the same period.