CatLin wrote:I have a question: you said dashes were used to set off a parenthetical comment -- why or when would one use dashes instead of parentheses?
If you've read the previous comma lessons, then you know that commas are also used to set off parenthetical material.
It's a matter of emphasis to determine when you'd use each one.
Parentheses indicate more emphasis than commas.
Dashes indicate more emphasis than parentheses.
Following that logic, then:
Dashes - most emphasis
Commas - least emphasis
Dashes indicate a longer voice pause than commas.
Use dashes to set off appositives which contain commas or semicolons. (Appositives are nouns, pronouns, or noun phrases that describe or explain another noun, pronoun, or noun phrase.)
Janis invited her friends--Susan, Mary, Gerry, Sam, and Jim--to her pool party.
Use dashes to add "afterthoughts."
I should have dealt with fixing the tire sooner--like yesterday.
Dashes and parenthesis can incorporate a complete sentence.
They finally sold their house (they'd lived there for 32 years) in January.
They finally sold their house--it had been listed for two years--in January.
I think of using parentheses as more of adding an "aside." Pertinent, "by the way" information.
Guy W. (who was also the founder of the Calgary Stampede) had a ranch in southern Alberta.
Hammond Elementary School (the building was torn down and rebuilt in the 1990's) will celebrate its 100th anniversary next year.
Remember that anything set off in commas, dashes, and parentheses are not essential to the general meaning of the sentence, and do not interfere with the grammatical structure of the sentence. In other words, if you remove the material inside the commas, dashes, or parentheses, you MUST still have a grammatically correct sentence. (The exception is dialogue.)
Use dashes and parentheses sparingly.
Did I cover everything?