comma chemistry

Commas act like chemical valences, bringing together two separate sentence elements into a more expanded sentence:
  • two independent clauses can form a compound sentence--e.g., "Mariana plays the flute, but Johann plays the harpsichord" ; "Derek is growing eggplant in his garden space, and his sister Bettina is growing rutabagas in hers" ; "We must write them in Japan soon, for we need that document that they alone have" (the coordinate conjunctions but, and, and for join two sentences which could have stood alone, but which we now want to combine).
  • one independent clause (an S-V-C: subject-verb-complement) joins with a dependent clause or dependent phrase, in order to form a complex sentence: "Valenzuela was a pitcher, while Bret Boone is a second baseman" (the subordinate conjunction while clues us that we have a subordinate dependent clause to join to our independent [potentionally free-standing] clause about Valenzuela); "Valenzuela was a pitcher, regularly winning exciting games for the Los Angeles Dodgers" (the present participle winning tells us that we have a dependent participial phrase to join to a main independent clause); "He sent love letters to the 'girl' he had become smitten with, who was actually (alas!) secretly married, already, to his Cousin Enrique" (the relative pronoun who clues us that we are adding a subordinate defining relative clause to help explain the main free-standing clause about smittenness with which we began).
NINETY PERCENT OF THE TIME (or even more)-- IF YOUR WOULD-BE EXPANDED SENTENCE CONTAINS SUBORDINATE CLAUSES, PARTICIPIAL PHRASES, OR RELATIVE CLAUSES--you can enhance the clarity of your writing if you punctuate between clauses or between clauses and dependent phrases with a comma (or perhaps, sometimes, with stronger punctuation like a dash--using such a dash when your sentence already is subdivided by commas).

Examples of COMPLEX SENTENCES formed by a main clause and a dependent clause headed up by a subordinate conjunction:

Because I could not stop for death, He kindly stopped for me (E. Dickinson)

Since there's no help, come, let us kiss and part.

Although Guy de Maupassant is famed for his short stories, his novels are little-known.

Wheras Pilar suffers from hives when she meets strangers, her sister Letitia likes to meet new people in new situations.

After he fried the eggs, Vasco poured salsa atop them.

Unless you have an aversion to visiting Parent's Day, we wil go there and thus support our children.

If P is true, the Q must also be true.



Examples of COMPLEX SENTENCES formed by a main clause and a dependent participial phrase:

I hate to be near Goat Boy, whose bad breath is notorious.

She longs, before she dies, to visit Tahiti, where her parents met during World War Two.

She told us to park between the two fire hydrants, which, we then sadly discovered, had been removed since her last visit to Clendenin.

Lyle said that we should be sure to visit Duluth in July, when (and only when) there would assuredly not be snow on the Northern Minnesota ground.

I used to love Suzette Desjardins, who had red hair, besides having hazel eyes as deep green as glaucous Swiss lakes.


Examples of COMPLEX SENTENCES formed by a main clause and a dependent participial phrase:

Dreaming constantly about being treated to a steak dinner at the J-R Ranch in Wisconsin, Paul forgot that his diabetic diet denied him more than a tiny bit of red meat (or any meat) daily. (-ing participle: present participle)

Denied love by the magnificently dressed Suzette, I decided to be a monk. (-ed participle: past participle)

Given that leopold has often been condemned as a horrific ruler over the Belgian Congo, one wonders if he should be revered by anyone (-en participle: past participle)


You should be punctuating when you see clauses or clauses and phrases coming together which use any of these kinds of subordinators, as well as when COMPOUND SENTENCES are formed by two full independent clauses that are joined by coordinate conjunctions.

The only times when these types of words DON'T call for commas are these:
  • when the entire sentence's purpose is to specify a very narrow definition: "The boy Magda loves is the one who has acne all over his ears, not the boy whose nose has ten bulbous bumps."
  • when the relative pronoun being used is that: "The dog that danced with Snoopy was named Dagmer."



written by Dr. Jeffrey Loomis 		    what would you like help in?
+ prewriting
+ thesis
+ paragraphing
+ organization
+ grammar & mechanics
+ argument
+ citation & sources
+ sample essays

 

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