Complex sentence: Adolph Saurer AG based in Arbon, Switzerland was a manufacturer of trucks and buses under the Saurer and Berna (beginning in 1929) brand names, active between 1903 and 1982.
Split into simpler sentences: Adolph Saurer AG was a Swiss manufacturer of trucks and buses under the Saurer and Berna (beginning in 1929) brand names. Based in Arbon, Switzerland, the firm was active between 1903 and 1982.