Use a colon only after an independent clause (a complete sentence) to introduce a concluding explanation, a list, an appositive, or a quotation. The element it introduces may or may not be an independent clause.
The business school caters to working students: it offers special evening
courses in finance and management.
If you really want to lose weight, you need give up only three things: breakfast,
lunch, and dinner.
The students' demands included the following: an expanded menu in the cafeteria,
improved janitorial services, and more up-to-date textbooks.
The Metropolitan Museum in New York City now owns the best-known works of
Louis Tiffany's studio: those wonderful stained-glass windows.
The little boy in E.T. did say something neat: "How do you explain school to a
higher intelligence?" - George F. Will
NOT The three meals are:
breakfast, lunch, and dinner.
People misuse punctuation marks such as: colons, semicolons, and dashes.
Handbooks provide valuable information about grammatical conventions
including: subject-verb agreement, pronoun-antecedent agreement,
Use a semicolon instead of a period between independent clauses that are
This is my husband's second marriage; it's the first for me.
Use a semicolon when conjunctive adverbs (therefore, however, etc.)
transitional expressions (in fact, as a result, etc.) connect two independent
The average annual rainfall in Death Valley is about two inches; nevertheless,
hundreds of plant and animal species survive and even thrive there.
3. Use a semicolon between long or comma-containing items in a series.
Functioning as assistant chefs, the students chopped onions, green peppers,
parsley; sliced chicken and duck meat into strips; started a broth
simmering; and filled a large, low, copper pan with oil before the head
chef stepped to the stove.
Use the dash, or a pair of dashes, to indicate sudden changes in tone or thought or to interrupt a sentence's structure to add information--either in the middle or at the end of a sentence.
(definition) Although the emphasis at the school was mainly language--speaking,
reading, writing--the lessons always began with an exercise in politeness.
(appositive) Two of the strongest animals in the jungle are vegetarians--the
(contrast) Tampering with time brought most of the house tumbling down,
and it was
this that made Einstein's work so important--and controversial.
(emphasizing an aside) Television showed us the war. It showed us the war
way that was--if you chose to watch television, at least--unavoidable.