Complex sentence: One of Smilansky's main findings in her research was that children engage in four types of play: functional play, conditional play, games with rules, and dramatic play.
Split into simpler sentences: One of Smilansky's main findings in her research was that children engage in four types of play. Smilansky found that children engage in four types of play: functional play, conditional play, games with rules, and dramatic play.