51.   But it is clear she sees forces at work hounding the president.

52.   But one scene provided an eerie symbol of the powerful forces at work today in the region.

53.   But scientists have improved their understanding of the forces at work in these incredible upheavals.

54.   But myriad forces at work in the economy threaten to end this long period of low inflation.

55.   But the long-running battle has illuminated the issues and forces at work when scientific controversies land in the courts or legal ones wind up in the laboratory.

56.   But Rey Sanchez bobbled the ball in a hurried attempt to get a force at second.

57.   But the forces at work here, some experts say, have been especially powerful.

58.   But there are also other forces at work.

59.   But there were more powerful forces at work.

60.   But there were no signs of U.S. forces at the front line.