Fairly simplistic test if you know the answers (they all are if you know enough so bit blinkered I guess to call it simple), slipped up on one question so got 19/20. Honestly though, if you didn’t get higher then 17 + which seems to be the average for this who’ve posted their scores, then it’s no big issue.
Not everyone is as good with English. Heck, my spelling and grammar is appalling. For this who’ve tried this test and scored low and are too embarrassed to post your score – don’t worry. Just use it was a way to try and increase your awareness and learn from it.