you can say " Can I have a medium(small, large) drink" instead of " I want a coca(扣可)", because you can choose any drink you like by yourself. I've never been to the Canadian Mcdonald's before, but i think it's more similar with the America's.
ingrid(樱桃)
My favorite is Chicken Nuggets and fries with some extra ketchup or barbecue sause.
But the kids would like Mcflurry.