21.   Researchers suspect it has to do with endorphins.

22.   Researchers suspect that either the doctors did less thorough examinations of the African-American patients or the patients did not disclose full information to the doctors.

23.   Researchers suspected that the process had a number of orthopedic applications as well.

24.   Researchers also suspect, but have trouble proving, that athletes who overdo it compromise their immune systems.

25.   Researchers had long suspected that cancer patients were more likely than healthy people to be forthcoming about potentially embarrassing factors that might have contributed to their illness.

26.   Researchers have long suspected that autism and mental retardation are caused by faulty brain wiring or abnormal brain chemistry that are present from birth, Nelson said.

27.   Researchers have long suspected that the reason could simply be that their strokes are more severe.

28.   Researchers suspect a possible biological basis for the differences.

29.   Researchers suspect that people may have picked up the resistant strain from food.

30.   Researchers suspect that women who develop breast cancer may be more willing to reveal potentially embarrassing facts about their past, including having once had an abortion.