"...It would be marked as incorrect in a formal essay, " As I said above, it depends on what kind of teacher you're dealing with. Some people think it will always wrong, some just don't care, and some think it's perfectly acceptable. Grammar is a funny thing. One thing that was correct one hundred years ago may not be correct now, or vice versa. Language likes to evolve, and right now (as far as I know) it's gravitating towards "they" being sometimes correct. There's no absolutes here. I wouldn't be surprised if 'they' is considered completely correct and simply another way to write in the future. Blame it on the fact we don't have a singular gender-neutral pronoun in third person, I guess. But, since the debate is if "they" can ever be formal, not if it's grammatically correct, we have come to moot point because this site is very informal. Therefore, the OP is techincally correct in this case, no matter how odd it sounds. {Btw, I wouldn't dismiss a dictionary that quickly. They're meant to inform you about the usage of words, so let them inform you about the usage of words.}

highschool sucks. fortunately most college teachers don't... unless they're old and senile

my two teachers do that to me all the time! but I draw instead of doing my lame work from social or we have math plus another math class (its horrible) xD so I kinda deserve lectures but when I actually do my work and draw after they don't believe me and say I copied! which aint always true! lol So thats on me but I hate when you tell the truth and you still get in trouble, hey I actually was told by the pride room teacher (no lie pride is like prison in school you cant do anything but work and stare straight all day or they yell in your face!) so he tells me I skipped 8th periods and I never got an 8th the one time I am on a doing all my work role and I am called up to pride for no reason having no classwork left so I literaly stared at the wall for the whole school day (about 7 hours) no lie I swear! and I get bored just staring at a wall for 1 minute who wouldn't! and yeah thats how I spent my friday and was a bitch all day after school because of it xD

when this type of thing happens and you are in the right you need to go to the principal's office and report it. the teachers should not abuse their authority and should listen to you!! Try this and hopefully your teacher will get yelled at by the principal.

why are teachers so dumb

How is this an FML? it's your fault your an idiot and don't know about the constitution. If you live in America, the first amendment states free speech. Read your school's guidelines and check if your actions broke any rules, if not then your not liable to face any punishment. Teacher's try to get me with insubordination all the time, I tell them my rights and move the **** on. I never go to detention anyway, **** that.

is your teacher acting like the classroom is her country and she's the queen?

Um, why didn't you just show the teacher your finished homework? Duh.

I frekin hate teachers like that u should have taken it up with a higher athoroty like a dean or princible

and you should be happy your parents care too much. Otherwise you might end up like one of these gangbangers in south central. your parents actually give a damn about your well-being.