@Sentinelle How do you know that? I've a Bachelor in English literature and I would be unable to say with certainty what were common mistakes among my fellow students 
The only thing I know is that Word or Grammarly, by default, consider the space before the punctuation mark as a mistake, and both highlight it. Since most students (afaik) write their essays with those, I would assume this mistake has become pretty unusual by now.
I meant to say that it's a common mistake, not that they're dumb or anything, by the way.
A teacher said it in class and people were shocked to learn that you don't put a space before the question mark, so it's safe to assume that it's not something most people know.
Even if you read english texts everyday, you don't necessarily pick up on the fact that the punctuation is different, I still see the mistake all the time on my classmates' word files, which is honestly not that big of a deal.
