Final answer:
The sentence illustrates the rising action part of the plot structure, leading up to the climax of the story.
Step-by-step explanation:
The sentence from paragraph 3, "The wind was then much higher, and I heard the master say to John that he had never been out in such a storm; and so I thought, as we went along the skirts of a wood, where the great branches were swaying about like twigs, and the rushing sound was terrible," illustrates the rising action part of the plot structure. This is because it is describing the events leading up to the climax of the story, where the tension and conflict are building. It sets the stage for the main showdown and central event of the story.