I am the forum dunce then as I only got 8 and couldn't understand many of the questions!
Unless you were a professional grammarian, you wouldn't. Many of these types of quiz exist, and it amused me no end when a friend who's a professor of Medieval English at Oxford couldn't get them all right.
It's far from rubbish, however, but it
is specialist - and there's a difference. This particular quiz uses terminology which is fairly arcane in nature and which has little or no relevance to writing or reading accurately. And there's a school of thought which attributes most of the currently 'correct' ways of writing and speaking to a Victorian who was short of a few bolts.
As English is essentially a form of Low German, it's little wonder it's 'rubbed off', Mike