Correct usage with adverbial clauses

Question

She forces him to help steal the money, then she blackmails him and takes it for herself.

First he said that he was right leaning, now he's saying he is left leaning.

He'd lost all his money on the pools, not that he cared about losing anyway.

It overstays its welcome by 20 minutes or so, just long enough for us to begin to feel restless.

Do any of these sentences require a period instead of a comma, and is so acting as a conjunction in the last example also.

Not sure with using 'just' in terms of it being a dependent clause?

Answer 1

All of these are correct as they are, but the reasons are tricky.

• In "she forces him to help steal the money, then she blackmails him", then is probably best analyzed as a conjunction: it could be replaced with "and" without changing the grammatical structure. (This may be controversial.)

• In "first X, now Y", X and Y are contrasting alternatives. It's possible to connect them with and or but, but it's not necessary.

• "X, not that Y" is a special construct: it says that from X, you might expect Y to be true, but it isn't. In this case, it sounds like the subject "cared about losing", but actually he didn't care.

• "So" isn't a conjunction, it's part of "or so": "20 minutes or so" means "about 20 minutes". "20 minutes or thereabouts" is another form meaning the same thing.

• "Just long enough for us to begin to feel restless" isn't an adverbial clause, it's modifying "20 minutes or so". So the whole sentence is equivalent to "It overstays its welcome by about 20 minutes, [which is] just long enough for us to begin to feel restless."