I am from Denmark and my English teacher insists on 'they' being grammatically incorrect when it is used in a singular sense (their hand reached...) No matter what I tell her she is convinced it's incorrect. Are there any "official" rules regarding this matter?
1 Answer
There is a debate about this, which can be described as "prescriptivism" (how language should be used) and "descriptivism" (how it is actually used). It seems you and your teacher are in different camps!
For more on the two schools of thought, see http://www.ling.upenn.edu/courses/ling001/prescription.html
For more in support of your position, see https://motivatedgrammar.wordpress.com/2009/09/10/singular-they-and-the-many-reasons-why-its-correct/ and http://www.oxforddictionaries.com/words/he-or-she-versus-they
But in the end, she will be grading your papers!