Answer the questions(根据以下内容回答问题)
In recent years, a number of Chinese technological innovation(科技创新) have been making waves around the world. Among them, four stand out. They are known as "four new great inventions" of modern China. They have made our daily lives more convenient
High-speed trains
China created its first high-speed railway line in 2008. Since then, the number of passenger trips has grown by over 30 percent every year. By 2016, more than 5 billion trips had been taken China's bullet trains(高铁), according to Xinhua News Agency.
China is currently working on the next-generation bullet trains that will have a top speed of 400kilometers per hour. By 2020, one-fifth of the country's 150,000-km railway network will be used by high-speed trains. This network will link more than 80percent of major cities across China, said Xinhua.
Mobile payment
Mobile payment is turning China into a "cashless society" led by third-party payment companies like Alipay. For example, instead of paying y cash, customers now pay for goods simply by typing a short password into Alipay app on their mobile devices.
Users can also pay their bills through Alipay, such as their water and electricity bills. Alipay also supports cross-border(跨境的)online and in-store payment, which allows users to buy things on international websites and apps.
Shared bikes
Shared bike services started in Western countries. But China has surprised the world with how quickly it has adopted dockless(无桩的)shared bikes.
Unlike traditional bike-sharing method, dockless bikes allow users to simply pick up or park a bike on the street through GPS and smartphone To unlock a bike, you just need to scan a QR code on a shared bike with a smartphone app After you finish riding, you can park it at available parking areas, lock it and pay for ride through mobile payment services.
Online shopping
With around 751 million internet users, China has long been the world's largest and fastest-growing online shopping market.
Online shopping now accounts for 15.5 percent of total retail sales in China, according to Xinhua. Thanks to lower costs and fewer licensing requirements(执照要求),it's easier for sellers to open an online shop in China than a brick-and-mortar shop(实体店)。
It also helped to create jobs of rural areas. In 2016, online shopping created more than 20 million jobs in rural areas, with over 8.1 million running their own online shops, said Xinhua.
