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Q. When using an ellipsis in a quotation that contains a full sentence and then deletes some of the next sentence, do you use a period at the end of the full sentence followed by a space and the three dots? Then do you capitalize the first word of the next sentence and do you bracket the first letter to show it was not capitalized?
A. That’s right, assuming that what follows the ellipsis is a grammatically complete sentence despite the omission. Please note that it’s usually not necessary to bracket the newly capped letter. Do that only if you are quoting in a legal or scholarly context that lends significance to the changed case. You can see an example of this at CMOS 13.53, where the changed cap is not noted with brackets.