Is "the" used in the following, and why?
I've been learning Latin since [the / no "the"] first grade.
I think that "I've been learning Latin since first grade" and "I've been learning Latin since the first grade of high school" both sound more natural than their alternatives "I've been learning Latin since the first grade" or "I've been learning Latin since first grade of high school", but I'm not certain why.
I suspect that it depends on whether the main focus of the sentence is the learning of Latin, or whether the main focus is the year of school. Is it kind of like saying "I've been learning Latin since 2011" versus "I've been learning Latin since the year 2011"?
The post With or without 'the' in "in (the) present participle form"? doesn't seem relevant, and this one is about "after" rather than "since".
Best Answer
No, it has to do with the "of high school" part. Since you could mean the first grade of elementary school, or the first grade of high school, each of which are a first grade, you use the to emphasize you mean a certain first grade, the first grade of high school.
Also, in American English, "first grade of high school" sounds very strange. We generally number grades from the beginning of elementary school, and keep using higher numbers through middle school and occasionally high school. (High school grades are often called "freshman year" "sophomore year" "junior year" and "senior year" instead of the equally correct but less common ninth, tenth, eleventh and twelfth grades.)