You don't know if he has been 'taught properly' or not. Grammar is a very important part of the curriculum, and pupil progress is monitored much more closely than it used to be. Despite this, some people still make grammatical errors, often for phonetic reasons that vary from region to region...
Blimey!
Yes, I am a teacher. I don't know why you feel that this is relevant, but once again I am forced to defend myself because people don't like my profession...
I have run sports teams for many years, football and cricket, athletics and swimming, with a lot of success. I strongly believe...