Am I annoying you with the Nouns of Direct Address?? Perhaps you should check out the Dynamic Dialogue tip Erynn posted earlier this week.
I promise to behave now, though. No more name-dropping.
Last week, I talked about the difference between compound and complex sentences. I promised I'd tell you how to look at a sentence and know if a comma is necessary. Without further ado...
Commas are good friends. They like to hang around, be useful, help out whenever they can.
They don't like to be taken for granted.
Look at that face! Don't abuse the poor guy. He trusts you not to put him in a bad situation.
Let's take a gander at two independent clauses:
Commas have sweet, little tails.
I think commas are cute.
We can combine these as a compound sentence (by using a comma PLUS one of the FANBOYS (For, And, Nor, But, Or, Yet, So).
Commas have sweet, little tails, so I think they are cute.
Or, we can blend these two sentences by leaving one of them strong and independent and demoting the other to subordinate status. We'll do this by using a WWW.ASIA.WUB subordinating conjunction--When, Where, While, As, Since, If, Although, Whereas, Unless, Because--or a Who/Which clause.
I think commas are cute, since they have sweet, little tails.
When you combine two sentences using the FANBOYS or WWW.ASIA.WUB, you've got to use a comma.
A who/which clause, though, might not have to be separated by a comma. It depends on whether the subordinate clause is restrictive or not.
What in the world does that mean?
If the subordinate clause is crucial to understanding the meaning of the sentence, then it's restrictive. Without it, a reader or listener could get confused. For example:
Run into the house and pick up the stack of books which is on the table. I forgot to return those to the library.
I don't know about your house, but at MY house, there are several stacks of books around. And if my child runs in and grabs the stack I just checked out for this week's research, then he's made a mistake. He needed to listen to ALL the information in my sentence.
Because the "which is on the table" was crucial to the understanding, it is restrictive and does not need a comma.
This is not restrictive:
Run into the house and grab the stack of books, which I immensely enjoyed reading. I forgot to return them to the library.
Frankly, it doesn't matter whether I enjoyed them or not.
One final thing before I jet:
Please do not forget the FANBOYS and my comma-friend if you want to combine two independent clauses.
That's a comma splice, it ain't nice.
Tune in next Saturday for more on that subject as well as the difference between a compound sentence, a compound subject, and a compound predicate. It's a big deal to get those right, folks. More possible comma mis-usage.
If you use them correctly, commas can make the world a beautiful place.