Complex sentence: Prior to 1976, the Dodgers were rained out only once, against the St.Louis Cardinals, on April 21,1967, ending a streak of 737 consecutive games without a postponement.
Split into simpler sentences: Prior to 1976, the Dodgers were rained out only once, against the St.Louis Cardinals, on April 21,1967. That rainout ended a streak of 737 consecutive games without a postponement.