since

The word “since” is often misused as a coordinating conjunction. In fact, its only appropriate roles are those of preposition, adverb, and subordinating conjunction. 

Unlike with coordinating conjunctions, a preceding comma is usually not required—and particularly not so when “since” means “because.” 

Two noteworthy exceptions calling for the use of commas are the insertion of parenthetical components in a sentence and the lessening of ambiguity when the preceding introductory clause is negative. 

Of course, as is true of all subordinating conjunctions—not only “since,” moving the subordinate clause to the start of the sentence requires that the relocated clause be followed by a comma.


The little dog is still incensed
Since finding skunk at fence;
Whene'er the scent of skunk is sensed,
Our dog will take offense.

And since the skunk was at the fence, 
There lingers yet a stench;
And that is quite important since
Our dog will want revenge.

So raucous a barking there was had,
The skunk we've not seen since.
Unrequited hate is surely sad;
Our dog may grief evince.
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*The key:
“Since finding skunk at fence…” (prepositional phrase)
“since the skunk was at the fence…” (subordinating conjunction, moved to the beginning of the sentence)
“since our dog will want revenge…” (subordinating conjunction)
“The skunk we've not seen since…” (adverb)
“Whene'er…” (like since, whenever is a subordinating conjunction; moved to the beginning of the sentence)

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