4个数字三个一组有多少种组合

简介：The Beijing Camp is divided into three major battalions. The Shenji Battalion is a firearms unit and is stationed in Jizhongfang; the Three Thousand Battalion is a cavalry unit, most of which are Mongolians, and is stationed in Baizhongfang. However, the two battalions are basically empty now and can only make do with it. In order to save face, the five military camps in the Beijing camp are still the most important. The five military camps are divided into the central army, the left Ye army, the right Ye army, the left sentry army, and the right sentry army.