A rhetorical question is one to which the answer is obvious or where the asker knows or confidently anticipates the answer. A statement may also be turned into a rhetorical question, often by adding a brief question such as “Are you?” or using an intonation more appropriate to a question.
The first chapter of The Woman in Black takes place partly on Christmas Eve. As Arthur’s stepchildren prepare to tell ghost stories, a family holiday tradition, one boy goes around the room turning out the lights. Isobel then asks a rhetorical question:
Must we have the lights out?
This is rhetorical because she knows, from previous years’ experience, that the answer is “Yes.” As the evening advances, the children and Arthur’s wife, Esmé, want Arthur to join in. Edmund pressures him, telling him to do his stuff, then teases him:
Stepfather, surely you’re not going to let us down?
This sentence is technically a statement. A question would typically be phrased “Are you going to let us down?” However, because the punctuation indicates the sentence was delivered as a question, Edmund’s comment about the story qualifies as a rhetorical question. He presumes that Arthur will answer in agreement.
Another example of this type occurs in the chapter “A London Particular.” Arthur recalls a day when Mr. Bentley began to tell him a complicated story, which he opened by saying,
I don’t think I ever told you about the extraordinary Mrs. Drablow?
“Did I ever tell you ... ?” would be a question, but here again the punctuation and intended response make this a form of rhetorical question.