"He had a sudden choking feeling, as if it were difficult to breathe." pg. 134. The change between Jonas keeping his feelings to himself in the book, to expressing his pain and sadness in the play by falling onto the ground, was an effective choice because in the book, Jonas keeps his feelings to himself and we aren't able to see how they affected him that much, but in the play, he falls onto the ground and starts thrashing around, emphasizing his emotions.
"As he continued to watch, the newchild, no longer crying, moved his arms and legs in a jerking motion. The he went limp. . . . 'He killed it! My father killed it!'." The similarity between the release of the newchild in the book and the play was effective because it is a crucial scene, that prompts Jonas to start thinking beyond his daily life. It forces him to consider running away, and therefore making his plan to go to elsewhere.
"'Twenty,' he heard her voice say clearly. 'Pierre.'" The similarity between Jonas getting skipped in both the play and the book was effective because both times, Jonas's reaction is a portrayal of his emotions at the time; confusion, panic. This leads him to wonder what's happening to him.