Couple of comma-splice questions

Question

1. He missed one episode of The O.C. and then played catch-up the rest of the season.

2. I have but one dream in life, to own a Harley-Davidson.

3. She swims twice a day, before school and right before dinner.

4. I passed up the offer although, come to think of it, I shouldn’t have.

Hi, I'm just kind of confused on some things.

If the first sentence doesn't need a comma before "and" because "then played catch-up the rest of the season" cannot stand on its own then why are there commas in the second and third sentence? Why isn't there a comma between "offer" and "although"? I thought a comma was needed before a conjunction.

Answer 1

The reason that 2 and 3 need a comma is because the clause after the comma is a parenthetical. Parentheticals are surrounded by commas.

"To own a Harley-Davidson" is an appositive because it defines 'your dream.' Appositives are always treated as parentheticals.

"Before school and right before dinner" is not an appositive, but it is a descriptive phrase. So it is treated as an parenthetical too.

For number 4, 'come to think of it' is an interjection. Interjections are also always treated as a parenthetical.

The rule that you are thinking of is, the comma should always be before a coordinating conjunction. Although is a subordinating conjunction.

You could argue that the sentence should be, without the parenthetical,

I passed up the offer, although, I shouldn't have. Or,
I passed up the offer, although I shouldn't have.  Or,
Although I shouldn't have, I passed up the offer.

This is not a technical answer, but, if you want the reader to pause after reading 'although', which bases on the parenthetical, you do, then the comma should come after. And, if you have a comma after 'although,' you don't need one before it aswell.