1. Tannin is a natural phenolic substance, which exists widely in plants. Tannins in wine mainly come from grape skins, grape stems, grape seeds and oak barrels. When tasting red wine, the dryness felt in the mouth is that tannins are at work.

2. Tanning is a foreign word, transliterated from denim, which refers to denim with twill weave and indigo dyeing, also known as denim. In other words, all jeans are made of denim. When it comes to the origin of cowboy clothing, it is natural to talk about the origin of cowboy. Denim, or denim in English. It is said that the origin of this name is somewhat wrong. Five hundred years ago, when Columbus discovered the New World, this tough and practical coarse cloth appeared, which was mainly used to make sails. Because this cloth originated in the small French town of Nimes, it was named "SergeDeNimes" in French. When this twill serge was first introduced to Britain, it was difficult for British businessmen to pronounce the French word "SergeDeNimes", so it was called denim for short, or denim, and sometimes transliterated as tannin.