This is what I used when we starting building a writing software:
1. The concept of chapter is only used to split the book for the benefit of the reader.
2. When you write your book you split the book in scenes (the smallest unit) with a location, POV, MRU structure.
3. Every scenes is on average 900 words. At the end you might split it in chapter to have an ...
That just means you use more short words than longer words, and have shorter sentences, right? In an of itself, that is not enough information to determine whether a story is worth reading or not for adults. You do you! If you're concerned about it, look for places where you could be clearer if you used more specific wording (which may be harder to read for ...
It depends on your target audience, right? If your writing is for elementary/middle schoolers, then yes, probably. But for high schoolers and above, it's okay to have it be complicated.
So consider who you want to read your stuff, and then edit accordingly. This can affect how you revise.
You should stop editing when you don't think you're significantly improving the writing any more.
With that said, now may be the time to have an outside reader give you feedback. You might also want to do an edit that isn't for any errors or deep structural issues, but that tightens up the work, and removes anything excess or extraneous, so that the final ...
To answer your question, it'll be something like this: "... I said, but I wouldn't." Then, the next person says, "Sure, but why?" It'll be best to use a comma unless you're trying to demonstrate that the person speaking is drawling out a specific word. Only use ellipses when your speaker is drawling a certain word.
Version 3 is the only consistent choice, except that the last item should have a period instead of a comma after the equation, and the "see" sentence should start with cap S and end with a period. Mathematical expressions do take a period according to The Chicago Manual of Style 12.18, which is academic style.
Song titles belong in quotes. If you're writing fiction think about the reader. Dialog uses double-quotes to frame the spoken word. In that dialog a song title can't also use double-quotes without potentially confusing the reader about where the dialog ends. So that is a good time to use single quotes.
"My favorite song," she said, "is 'Memories', or ...
The center justification is called a "block quote" and should be used when the quote is typically four or more lines. Typically I see songs broken in rhyming couplets for normal quotes, so you may want to break the quote in a format such that:
"[Song line one]," He sang, "[Song Line Two]"
I would treat it like it was a quotation. Because it is direct speech, it means that there would be inverted commas within inverted commas.
"'And you live a life worth living and you make my world --'"
By the way, you use a dash at the end which indicates he is interrupted, but you don't include the interruption.