The invention of barcodes（条形码）is based on a very simple idea. We only need to give each product a specific number and print it. 【小题1】We could simply print the number itself. But this can cause problems. For example, an unclearly printed “seven” could look like a “one” to a computer. It’s also true for “three” and “eight”. 【小题2】We need a better way of printing numbers so that they can be read correctly at high speeds. That’s the problem barcodes solve.

Each number in a barcode is shown by seven blocks of the same size. These are colored either black or white to show the number zero to nine. For example, the number “one” is shown in turn by two white stripes（条）, two black stripes, two white stripes, and one black stripe. 【小题3】

A barcode includes different parts and each one provides a specific meaning. The first part of a barcode tells you the country where the product was made. For example, 690—692 is the barcode for China. 【小题4】The final part is about the product itself. This is how barcodes work.

At an early age, Jun Jiang knew he wanted to develop technology. When he grew up, he moved to the U.S. to continue his education at San Diego State University. There he saw many Chinese students,like himself, facing difficulties in living in San Diego because of the language problem and cultural differences.

This led Jiang to develop a special app named “The sauce(调味汁) for Abroad— the Overseas Chinese Students’ Community Builder” on WeChat. Jiang said he used the word “sauce” to show that his app can make the life in America better for users.

Jiang’s app provides a place for sharing reviews, finding local housing, and offering dining places and sales, etc. So far, it has helped more than 100,000 Chinese students deal with the challenges of studying and living in the United States on their own.

Building a community through technology achieves Jiang’s lifelong dream of helping others be their best. Now Jiang, who will complete his studies this year, has a tech team of eight in China. They are trying to add more functions(功能)to the app. And he plans to attract more student users across America, Britain, Australia and Latin America in three years. “I’m trying my best to help as many people as I can,” Jiang said. He plans to continue with app development in the future.