Complex sentence: One day in May 1971 when Genie was with Jean Butler, Butler asked a boy holding two balloons how many balloons he had; when the boy said "three", Butler said Genie appeared startled and quickly gave him another balloon.
Split into simpler sentences: One day in May 1971 when Genie was with Jean Butler, Butler asked a boy holding two balloons how many balloons he had. When the boy said "three", Butler said Genie appeared startled and quickly gave him another balloon.