This is the 7629th most frequent Chinese word.
軍當
"軍當" refers to military duties or responsibilities.
In this sentence, "軍當" refers to the military troops collectively.
現在軍當訓練中，大家都很努力。
Currently, the troops are in training, and everyone is working hard.
Here, "軍當" is part of the phrase where it conveys the act of serving in the military.
他曾經軍當兵，學到了許多技能。
He once served in the military and learned many skills.
In this instance, "軍當" functions as a descriptor for the pioneering subgroup within the military.