After reading chapter 4 of 1984, what question could you ask someone that would cover the whole chapter?
If I had to ask one question for the whole chapter, I would ask something like this: "Why is Winston Smith's job so important to the Party?" By asking this question, I would A) encourage people to look at what his job is and B) get them to think about the society in which Winston lives.
Most of the chapter revolves around a description of what Winston does for a living. We see the sorts of things that he is changing in the official records, for example. We also see some of the details of how the process works. Therefore, a good question for the chapter should be about his job. At the same time, it is important to think about the importance of the chapter rather than just asking some factual question about the contents.