Can there be a comma before "or" in the last two exaples of yours? – user70587 – 2018-03-02T21:03:56.287

3@user70587 The third can (or should, depending on who you ask) be written with a comma; the fourth cannot be written with a comma under any circumstances. – LegionMammal978 – 2018-03-02T23:58:07.743

@LegionMammal978 I'm a native speaker and I would use a comma in the fourth, but only if I want to convey a pause. Is there some rule I'm not aware of? Edit: found the rule in the comments: use a comma only if the clause after the conjunction is independent. – wjandrea – 2018-03-03T00:13:23.700

2@wjandrea commas are not supposed to be used to convey a pause. – Kat – 2018-03-03T02:22:46.793

Is there supposed to be a comma before "or"? – user70587 – 2018-03-02T20:55:01.150

Well it's a conjunction here so I would say yes. – Element115 – 2018-03-02T21:03:21.260

2The common rule is: comma+conjunction only if the second half is an independent clause. So: "Should I give it to you or keep it to myself?" OR "Should I give it to you, or should I keep it to myself?" – Adam Michael Wood – 2018-03-02T21:21:55.967

^fair enough. I guess I glanced over the lack of a subject in the second clause. Thank you. Fixed it. – Element115 – 2018-03-02T21:23:29.257

Technically this sentence means something else (and the answer would be "yes" or "no"). However, for better or worse, I agree that this is a common shortening. – Lightness Races in Orbit – 2018-03-03T00:49:07.567

3

As a fellow American, "keep it to myself" has a strong implicature for "it" being a secret or a gripe, and sounds really weird when paired with "give it to you" in this way.

1I second @MarkS.' comment. I think the ideal phrasing would be: "Should I give it to you or keep it?" There's no need to add "myself" at the end, unless you want to make it clear that you wouldn't be keeping the item on someone else's behalf. In that case you could say "...keep it for myself". – DoctorDestructo – 2018-03-03T01:56:04.110