Complex sentence: During 1919 Knudsen became an Organizer for the International Association of Machinists (IAM): in 1920 Knudsen led 3000 machinists in a strike and held another strike consisting of 10,000 Machinists in 7-month strike in Cincinnati in 1920.
Split into simpler sentences: During 1919 Knudsen became an Organizer for the International Association of Machinists (IAM). The next year he would lead 3000 machinists in a strike and held another strike consisting of 10,000 Machinists in 7-month strike in Cincinnati in 1920.