For the past 3000 years, when people thought of money, they thought of cash. From buying food to settling bar tabs, day-to-day dealings involved paper or clinking bits of metal. Over the past decade, however, digital payments have taken off — tapping your plastic on a terminal or swiping a smartphone has become normal. Now this revolution is about to turn cash into an endangered species in some rich economies. That will make the economy more efficient, but it also poses new problems that could hold the transition hostage.

Countries are eliminating（消除）cash at varying speeds. But the direction of travel is clear, and in some cases the journey is nearly complete. In Sweden the number of retail cash transactions per person has fallen by 80% in the past ten years. Cash accounts for just 6% of purchases by value in Norway. Britain is probably four or six years behind the Nordic countries. America is perhaps a decade behind. Outside the rich world, cash is still king. But even there its dominance is being eroded. In China, digital payments rose from 4% of all payments in 2012 to 34% in 2017.

Cash is dying out because of two forces. One is demand — younger consumers want payment systems that plug seamlessly（无缝地 ）into their digital lives. But equally important, suppliers such as banks and tech firms (in developed markets) and telecoms companies (in emerging ones) are developing fast, easy-to-use payment technologies from which they can pull data and pocket fees.

In the main, the prospect of a cashless economy is excellent news. Cash is inefficient. In rich countries, minting（铸造）, sorting, storing and distributing it is estimated to cost about 0.5% of GDP. But that does not begin to capture the gains. When payments disappear, people and shops are less vulnerable to theft. Governments can keep closer tabs on fraud or tax evasion. Digitalization vastly expands the playground of small businesses and sole traders by enabling them to sell beyond their borders. It also creates a credit history, helping consumers borrow.

Many adults rely on caffeine to get them through the day. But that’s the last thing kids need, according to the governments of England and South Korea.

England woke up to the news that the government is preparing to ban the sale of energy drinks like Red Bull to children.

The ban only applies to England, but Scotland, Wales and Northern Ireland can all follow suit if their administrations wish. In March, several major supermarket chains announced they would ban the sale of energy drinks to children under 16. Meanwhile, South Korea announced plans to ban the sale of coffee in schools by September 14.

The first reason for the ban is the high level of caffeine in the energy drinks, which has been linked to health problems for children, including head and stomach aches, as well as sleep problems.

A 250ml can of Red Bull contains about 80mg of caffeine, roughly the same as a similarly sized cup of coffee, but three times the level of Coca-Cola. Monster Energy, which is often sold in larger cans of 500ml, contains 160mg of caffeine.

Energy drinks often also have higher levels of sugar than soft drinks. Sugared energy drinks have 60% more calories and 65% more sugar than normal soft drinks and sugar is one of the largest causes of obesity (肥胖症).

British national official for education, Darren Northcott, described the drinks as “legal highs” that helped to fuel bad behavior in schools.

In addition to limiting kids’ access to caffeine and energy drinks, the South Korean government has also banned TV commercials for fast food, sugary snacks and high-caffeine beverages during times when most children’s programs air.

South Koreans drink an average of 181 cups of coffee a year, by far the most in Asia. That is more than the 151 consumed per person in the UK but less than the average of 266 cups in the US.

Do you have a spare room in your house? Do you like to share your driveway in front of your garage with others? 【小题1】 Many people are benefiting from this new business of renting.

Perhaps the best-known example of a company in this field is Airbnb―an American Web business which allows you to rent out your spare room to holidaymakers. It says it operates in 34,000 cities and it has 800,000 listings of rooms and apartments. 【小题2】

A British company is doing something with parking spaces. JustPark's founder, Anthony Eskinazi, says, “When I had the original idea, I spotted a driveway close to a sports stadium. It would have been so convenient if I could have just parked in that driveway rather than in a commercial car park.” 【小题3】 Around 20, 000 people have advertised their spaces on the website and he says around half a million drivers use it. 【小题4】 They are people who run things like traditional hotels and commercial car parks. They are afraid of ending up losing money.

And there is another problem. Regulations for the new business are still unclear. 【小题5】 Because this is a new business world, those rules about appropriate manners aren't there yet.