Do you like eating raisins(葡萄干)? They are dried grapes that have been eaten (广泛地) for thousands of years. Nearly 3,500 years ago, the first raisins were (发现) as grapes that were drying in the sun on a vine(藤). In the past, Europeans used raisins as medicine and even as a (形式) of money.
In America, raisins were seen after an 1873 (高温) wave in California destroyed its valuable grapes, leaving only dried but tasty grapes. Soon, some (农民) began developing seedless(无籽的) grapes in California. These grapes would be (烘干) in the sun and became the popular dark raisins we eat and enjoy today. Later, there was a kind of golden raisin. It was made by treating grapes with a chemical(化学物质) and using some special methods to (加工) them.
Today, central California (保留) the center of the world's raisin industry. It can (生产) nearly 35 percent of the world's raisins, (它的) sunny climate and hot temperatures provide the perfect conditions for grapes that are dried into raisins.
