The daily-use glass factory has considerable profits. A glass factory can earn about 3 million a year and now works in a glass factory. There are more than 40 workers in this glass factory, and the annual income should be around 3 million. The investment in building a small glass factory is about 500,000 yuan, and the production capacity is 10 ton/day. The cost of glass is 800 ~ 900 yuan/ton, and the profit is about 2000 yuan/ton. The daily profit is about 10 ton/day. Monthly profit =30 days, 20,000 yuan/day = 600,000 yuan. In other words, if you sell glass at yesterday's glass futures price, you can earn 600 thousand a month, and the money for opening a glass factory can be recovered in one month.