Complex sentence: Big Brothers of America was supported throughout the 1960s and 1970s.In fact, in 1974, then Grand Polaris, Thomas Dean appeared in a local television commercial on behalf of Big Brothers of America.
Split into simpler sentences: Big Brothers of America was supported throughout the 1960s and 1970s. In 1974, then Grand Polaris, Thomas Dean appeared in a local television commercial on behalf of Big Brothers of America.