Original sentence: Many episodes used stock footage from previous 20th Century-Fox and Irwin Allen productions
Edited sentence: Everyone everywhere, in every time period, spoke 20th-century English.French and German characters have a stereotypical accent, while British, Greek and Afghan characters do not - yet Doug and Tony are still surprised when they find Native Americans who speak English in the Custer episode.Hand-to-hand combat, sword fights, and force fields are frequent staples.In many episodes, especially the ones on an island, the entire surface area in which Doug and Tony move is easily a small fraction of an acre.Many episodes used stock footage from previous 20th Century-Fox and Irwin Allen productions, in an effort to cut costs.The opening credits sequence is colorful and dynamic.Tunnel personnel find necessary research information almost always in hard copy form, such as books, charts, and maps, rather than from the computers, which other television series in the same years, such as Star Trek, employ.When people are hit on the head they get amnesia, and it's always temporary