Gonna, Gotta... Speak Like a Native English!

In this video, Alisha answers 5 questions. - What does 'to roll' mean in this context - 'Sugar was rare, too. If you could offer guests a feast featuring spices, sugar and vegetables from the New World, you were rolling.'? Is it about about madness or poverty? - What's the difference between gonna and gotta? And where I should use? - Could you tell me please which forms are correct? 1) a. I learned English in the morning, b. I've learned English in the morning, c. i've been learning in the morning, d. I was learning in the morning 2) a. We will be eating dinner when he arrives. b. We will be eating dinner when he arrive 3) Michael said: Yeah, "that" was a new one for me as well. I hope I don't have to do "that" again. Can I use "this" instead of "that"? - "Are you using me for my brain?" what does this mean?! You mentioned this in "100 Phrases Every English Beginner Must-Know". - When i say "things couldn't be better" does it mean in the past or i can use it to mean for the time being.