21.   Although Manning offered to step aside, Castillo said last week he had serious doubts about taking the case.

22.   American depository receipts were basically flat, but serious doubts by U.S. investors about prospects for the Mexican market lingered.

23.   And there were serious doubts as to whether cards and base stations manufactured before that would be upgradable to the new standard.

24.   And there are serious doubts about the constitutionality of vouchers.

25.   And yet for the major animal welfare groups in this country, there are serious doubts about how humane life in the circus is for animals.

26.   As for doing away with human characters and cartoons, there are serious doubts that this could happen.

27.   As it turned out, the top-seeded Heat is the team facing serious doubt and probable changes.

28.   As its difficulties mounted, state and city support for a rescue effort was in serious doubt.

29.   As Rubin sat there in a crouch, imploring the chair umpire to overrule, she began to have serious doubts.

30.   As the movie opens, Havilland has already caught Michael cheating once and has begun having serious doubts about their future.