Retired English teacher Yvonne Mason has spent much of her life correcting students' writing.
But it's a letter from the White House, signed by President Donald Trump, which has proved a pretty noteworthy correction exercise — and it's attracted plenty of attention.
"If it had been written in middle school, I'd give it a C or C-plus," she told The Greenville. "If it had been written in high school, I'd give it a D."
Mason, who retired last year after a 17-year career in South Carolina, corrected the letter she had received in response to her concerns following the February shooting at Florida's Marjory Stoneman Douglas High School.
"Got a letter from Mr. Trump. Will be returning it tomorrow," she wrote in a Facebook post showing the letter.
Mason raised issues including errant capitalization, redundancies, and a lack of specificity in the letter. She held back from putting a grade on the paper.
"When you get letters from the highest level of government, you expect them to be at least mechanically correct," she added.
The teacher recognized that the letter was likely written by a staffer. A recent report on Trump's Twitter account, suggested staffers intentionally insert grammatical errors to make it appear like the tweet has been composed by the President.