I knew that, because I taught it once
Most of the actual grammar I know is because I had to teach it
I think I have my supplemental material for my writing class tomorrow.
This is a good one for 20 questions. You can play a round of 20 questions with them and then you will have on the board a list of adjectives that describes the thing and then you can have them put it in the correct order.
was literally just teaching my students this last Friday!
I’ve been corrected more than once by my students when I’m speaking and I pronounce “a” with a “short a” sound instead of a “long a” sound, or vice versa. I’d never really known there was an actual rule to it, but apparently there is, and my students know it and I don’t. 
On this topic, it seems AI might accelerate the change in language. For example, when dictating, it shortens how I speak for example using wanna of kinda.
I’m starting to wonder if AI is going to destroy grammar: people are trying harder to NOT sound like an LLM, and in some cases that seems to be mean abandoning complete sentences.
I’m not sure there is a rule for it, other than emphasis/stress. Would you like one or two thing? I’ll have A thing
Otherwise, schwa for days. I mostly do long A with my students to emphasize that I’m using the article A, as there are many cases where it’s the correct article choice and that needs to be noted (I’ll have a… I want a… etc.) normal speaking, I’d use schwa a, and I do have them practice using that, but to initially teach the grammar I’ll use long A.
But yeah, my students have corrected me on it too. I just have to tell them “you’re not wrong BUT…”