Information that is directly quoted must be placed in quotation marks and provided with an in-text citation. Most importantly, the quotation must be exactly as the author has written it. To avoid any confusion as to who owns the information presented, always introduce your author or source somewhere in the sentence. You do not need to conceal the fact that you are borrowing information. In fact, be forward with your reader.
Changes to the quote, including removing words or changing the tenses of verbs for readability, must be noted with the use of indicators such as the ellipsis (three dots) or brackets.
The Ellipsis:
Eliminate words to blend the quote with your introductory words or to eliminate unnecessary information. Integrating your words with the direct quote will help build cohesion and unity within your text. When you eliminate words or entire sentences from a quote, you must indicate that you have altered the direct quote because now it does not appear exactly as it does in the original source. The ellipsis is the indicator you will use, and to create one, type three periods and skip spaces between them. An ellipsis that ends a sentence still requires a terminal mark of punctuation. Be sure to skip a space after the last and type the terminating period. Consider the following example:
Original: "Mary had a little lamb, little lamb, little lamb; Mary had a little lamb whose fleece was white as snow" (Goose, 1803, p. 4).
Words omitted: "Mary had a little lamb . . . whose fleece was white as snow" (Goose, 1803, p. 4).
Note: Work quotes into your writing as integration makes the borrowed information easily manageable by your reader. Example: According to Mother Goose, one of Mary's ewes birthed a lamb and its "fleece was white . . . " (Goose, 1803, p. 4).
Brackets:
Use brackets to indicate that you have added words or any other elements of the sentence for readability or to indicate incorrectness.
Original: "Looking over the side of the bridge created a dizzying effect in his behaviour, as he stumbled and fell."
Corrected Version: "Looking over the side of the bridge created a dizzying [a]ffect in his behaviour, as he stumbled and fell."
Original: Looking over the side of the bridge "can effect behaviour," as he stumbled and fell.
Revised: Looking over the side of the bridge "effect[ed his] behaviour," as he stumbled and fell.
If, for instance, the spelling of a word or the grammar used was incorrect in the original, you could indicate the problem within the quote by using [sic].
Example: "Looking over the side of the bridge created a dizzying [a]ffect in his behaviour [sic], as he stumbled and fell."