Elsewhere someone asked a question about the following sentence:
[I] - I ate the pie, and since then, I have had a stomach ache.
Please consider the following variation (comma placement):
[II] - I ate the pie and, since then, I have had a stomach ache.
- In example I, what is the rationale for having a comma before the "and"?
- Does example II make sense for the native speaker, and, if so, does the meaning differ from I?
- Does the grammatical function of what's enclosed with the commas vary between I and II; is what's left, when we remove both the commas and what's inside, a consideration in that respect?
I have taken a look at the CGEL. First I identified that you can have "since" alone with the meaning of "since then" for instance "...ever since"; but this is in the context of the realisation of terminal-point duration elements with adjuncts to clauses (chapter 8, p.708). Chapter 20 deals with Punctuation per se; I acknowledge the potential for variation. I'm trying to understand why you would(n't) include "and" in the subclausal constituents (p.1745) when using heavy-styled punctuation (p. 1727). Where I'm coming from, I'm thinking "if there was just 'and', and no 'since then', this would be more complete a sentence than the two parts marked with a single comma because is that even a sentence at all?" or... "why would you take a break in speech after the pie if you don't give a clue to introducing anything else; then shouldn't that pause be a period instead?". It's all very naive thinking, as I have no command whatsoever of formal grammar. I have asked questions accordingly.