41.   Radionuclides are unstable atoms that undergo a spontaneous decaying process that can last from a fraction of a second to billions of years.

42.   Retreats can last from one day to eight or more days, Powers said.

43.   She and Sternlieb began a debate about staying at home or going away to college that lasted from fall to spring.

44.   Signs of robust demand comes during the peak demand period for U.S. chocolate consumption, which lasts from Halloween at the end of October through Easter in April.

45.   Some excursions lasted from first light until dusk.

46.   Symptoms can include fever, jaundice, abdominal pain and nausea, lasting from a week or two, to several months.

47.   Tension-type headaches last from a few hours to a day.

48.   The arthritis can last from a few days to a few months, but if the Lyme infection goes untreated the arthritis may become a chronic problem.

49.   The burning season lasts from July through to November.

50.   The battle lasted from noon until sunset.