From the nature of the question, I think that there is some level of prediction required. Based on where you are in the reading, you are being asked to project into the rest of the text. With this in mind, I would actually flip this on you with a couple of questions. The first would be to examine Rebecca Nurse's character in Act I. What are some of the behaviors she projects? How are these different than most of the people in Salem in the Act? This will be critical in seeing what her role is going to be throughout the work. It is how Rebecca is presented in Act I that is going to be present throughout the work as a reminder of how good people can be. This is essential. As the town devolves into further madness and greater resentment, people like Rebecca will serve as the penultimate reminders of how human beings can be as opposed to how they are. This is vitally important and something that can serve as a reference point throughout the play. Examining how Rebecca's characterization is developed in what she says and believes and how others respond to her are critical elements in assessing her impact on the play as a whole.