​Use a colon after an independent clause to introduce a list of items.

​To make this recipe, we need the following items: 2 cups of flour, 1 egg and 3 egg whites, 1/2 cup of sugar, and 1 cup of cocoa powder.

​Use a colon to introduce a formal or lengthy quotation.

​As Albert Einstein once said: "Not everything that can be counted counts, and not everything that counts can be counted."

​Use a colon to introduce a sentence that summarizes or explains the sentence before it. Capitalize the first word in each.

​I have a very good reason for cooking the steak medium-well: Undercooked meat is unsafe.

​Use a colon in numerals giving the time, salutations in formal business letters (not friendly), and references to periodicals and the bible.

​11:23 P.M. Dear Mr. Greer: Numbers 3:40

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