Please give me a source that states this so I won't make the mistake in the future.
Hi, Tabac. I'd happy to hazard a guess at your request. As I'm not an expert at discovering a source, here is my rule of thumb:
We can
, either or not
, put a comma in between a lengthy sentence
, whenever a natural pause occurs at any place of the sentence in question
, and we need to take a fast and shollow breath, so that we can go on reading it
, without being out of breath.
Well, this sentence doesn't make much sense, yet it indicates that some of the comas, which show a natural pause, are optional.
Hopefully, this makes some sense to my friends.