For example, if you need to supply a character's name where a quote has a personal pronoun, or a pronoun for a noun. Indicate breaks in quoting with ellipsis points. In general, however, use a blank space, three points, then another space when you omit material in the middle of a sentence, and four when skipping between sentences. If you break at the end of a sentence and then move to another, include the final punctuation mark from the first sentence. Rome had several mad emperors.
Legend has it . . .
For example, if you cited the quote above as a fact rather than a legend about Nero, you'd be misrepresenting the original author's intention. Double-check the original. Avoid long quotes when a short one will suffice. Don't take quotes out of context to misrepresent the original author's opinion. Read the entire source carefully if possible.