A warning system to prevent people from falling asleep while driving     1     ( introduce) at the China International Fair for Trade in Services. It can judge whether the driver is sleepy     2     monitoring how long the driver’s eyes close or if his or her head drops.     3     the driver enters a state of tiredness, the system will immediately sound an alarm until the driver’s eyes reopen.

In 1863, the first underground passenger railway in the world opened in London. It     1    (run) for just under seven kilometers and allowed people     2    (avoid) terrible crowds on the roads above as they travelled to and from work. It     3    (build) using an interesting method. This included digging up the road, laying the track and then building a strong roof over the top. When all those had been done, the road surface was replaced.

Different countries have different bicycle-sharing systems towards children. Chinese children are welcomed on the country's using bicycle-sharing systems at age 12. In Paris, 14-year-old children     1     (allow). The age minimums for US bicycle-sharing systems   are generally 16 or 18. Research shows children    2     do some exercise in the morning concentrate better in school. When more people ride bikes, air quality improves, aiding everyone's health. Having a bicycle also teaches responsibility and    3     (confident). People learn how to ride    4     (safe) on city streets and respect rules of the road. When   students are riding in the street , there’s a real ownership that they feel over their city. Of course, it's very important for riders to understand traffic rules.

Ten years ago, people bought electric vehicles (EVs) to reduce their carbon footprint.     1     the limited range and high price made EVs something of a rare sight on roads. A lot can change in a decade. Advances in battery technology     2     (mean) electric cars now travel much further on a single charge. Government grants (补贴) serve to draw buyers away from gasoline-powered cars. The change will have a huge impact     3     life. Roads will become far     4     (quiet) and pollution levels will be reduced quickly, potentially leading to improved quality of life.

In most big cities, it is easier to hire a taxi at a moment’s notice when the weather is good. But when it’s raining, people have a much harder time     1    (find) one. One obvious reason is that many people who walk short distances during good weather prefer to take a taxi in the rain.     2    , taxis tend to be more fully occupied on rainy days. Besides, the supply of available taxis is also smaller because taxi drivers can     3     (easy) reach the target fares and go home early.

The railway line     1    (connect) Beijing and Zhangjiakou, the co-host city of the Beijing 2022 Winter Olympics, is the world's first intelligent, high-speed railway. It     2    (go)into operation on Dec 30, 2019. The railway is 174 km long, with a maximum design speed of 350 kph. It reduces the travel time between Beijing and Zhangjiakou from over three hours to 47 minutes. The train is designed with an area to store snowboards, a device to secure wheelchairs and a mobile news center     3     passengers can watch live Olympic broadcasts.

In the early 1800s, Stanislas Baudry built public baths in the center of a town in France. To encourage people to come, Baudry drove a large vehicle around to give people a ride to the baths. He called the vehicle an omnibus,     1     is a Latin word meaning “for everyone”. Then he     2     (notice) that many passengers would get off at stops during the journey to the baths. So Baudry shifted the focus of his omnibus service. He created a permanent route for passengers     3     (board) and get off. Eventually, the omnibus became known     4     (simple) as a bus.

10 . Bicycles,     1     used to be a major means of transportation, are becoming popular again. New York City, together with London, Paris, Hangzhou and many other     2     (city) throughout the world, gets bike-sharing systems of their very own. More and more people are considering using bikes     3     a replacement for cars, and how to improve bike-friendly crossroads is also under discussion.