North American continent. For the purpose of keeping warm, autumn trousers in modern society tend to be slightly elastic. Officially originated from the North American continent, wearing one-piece underwear to keep out the cold in winter. Its style is to wrap people's upper and lower bodies and tighten their wrists, which is a set of seamless autumn clothes and trousers. With the rapid development of clothing and textile fabrics, there are countless fabrics such as wool, cashmere and blended fabrics, and their warmth retention is getting stronger and stronger. There are more and more substitutes for leggings and compression pants, and cotton autumn pants are no longer the first choice for warmth.