Complex sentence: Many quarrels arose between the KSČ and the remaining parties of the National Front in the transitory period 1945--1948, until the KSČ definitively seized power in Czechoslovakia on 25 February 1948.
Split into simpler sentences: Many quarrels arose between the KSČ and the remaining parties of the National Front in the transitory period 1945--1948. The KSČ definitively seized power in Czechoslovakia on 25 February 1948.