Complex sentence: In the United States, the first episode of the series originally aired on "Howdy Doody" in 1955; the series was revived multiple times, with the last episode airing on December 31,1989.
Split into simpler sentences: In the United States, the first episode of the series originally aired on "Howdy Doody" in 1955. The series was revived multiple times, with the last episode airing on December 31,1989.