(1) A colon is used when telling time.
(2) Use a colon when there are two sentences and the second sentence explains the first. (Replaces the word "because")
(3) Colons can be used to list objects.
(4) Use colons when introducing a quote or formal statement.
(2) Sally was tripping on shrooms the day before the final exam: She is not very smart.
(3) You need to get these items from the store: Beer, beer, and more beer.
(4) Like Suzy always said: "Don't touch anything."