Complex sentence: Additionally, in the days following the Shelling of Mainila, the Soviet propaganda machine generated publicity about other fictitious Finnish aggressions, renounced the non-aggression treaty with Finland, and on November 30,1939 launched the first offensives of the Winter War.
Split into simpler sentences: Additionally, in the days following the Shelling of Mainila, the Soviet propaganda machine generated publicity about other fictitious Finnish aggressions. The Soviet Union then renounced the non-aggression treaty with Finland, and on November 30,1939 launched the first offensives of the Winter War.