Why do Tibetans wear Tibetan robes with one hand exposed?

Personal opinion, just personal opinion, Tibetans originally lived in the grasslands, or nomadic life, warmth is a must, so the Tibetan robe is very thick, because it is a nomadic life, all the things basically rely on self-sufficiency, hard work is also inseparable from, you imagine, if the two sleeves are wearing the action will not be very inconvenient, so show a hand will be separated from the clothes, the action will be much more convenient The Tibetan robes are worn by the Tibetan people. p>