Each one of us shares this planet with seven billion others. And we all need 1 . People and products need to move from city to city and country to country. However, we all know2 most cars, motorcycles boats and planes cause air pollution. They are also 3 . This is a serious problem in many cities. 4 inventors are coming up with creative ideas to try to reduce the pollution and noise.
In many cities around the world, motorcycles are very 5 . Now Vietnam has around 33 million motorcycles and China has almost 120 million. Motorcycles are a faster and cheaper way to get around a city than6. Yet air pollution is a growing problem. In large cities, people 7 it is difficult to breathe. To solve these problems, a US company designed an environmentally friendly motorcycle . It uses electricity as fuel( 燃料). As a result, there is 8pollution. It's also quiet and fast. This makes 9 a good choice for getting around a city.
The Italian city of Venice is a city with only a few10. There are no cars in the city center. 11 cars, water taxis and buses carry people along the city's canals （运河）. However, they cause pollution，12 to the water. English engineers Dick and Jem designed a solar-powered（太阳能 water taxi. The water taxi 13 run for a day after being recharged(充电).
Planes also cause air and noise pollution. Designing an environmentally friendly airplane is a real 14 . Some airplane companies have 15 to solve the problems. Swiss engineers have gone one step further. They developed a solar airplane. This plane holds the world record for the longest solar-powered flight-1, 541 kilometers from Arizona to Texas in America.
