This is the 8007th most frequent Korean word.
a군을
"a군을" is a grammatical structure in Korean, meaning "group A" or "A group" and marks it as the object in a sentence.
In this sentence, 'a군을' refers to a specific person ('군' often used for young males in Korean).
나는 a군을 만났다.
I met Mr./Miss A.
Here, 'a군을' again refers to a specific individual, placing them as the object of the verb.
그는 a군을 기억하고 있다.
He remembers Mr./Miss A.
In this instance, 'a군을' represents the beneficiary of the action described.