Each one of us shares this planet with over seven billion others. And we all need1. People and products need to move from city to city and country to country. However, we all know2most cars, motorcycles, boats and planes cause air pollution. They are also3. This is a serious problem in many cities.4inventors are coming up with creative ideas to try to reduce the pollution and noise.
In many cities around the world, motorcycles are very5. 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, people7it is difficult to breathe. To solve these problems, an American company designed an environmentally friendly motorcycle. It uses electricity as fuel (燃料). As a result, there is8pollution. It's also quiet and fast. This makes9a 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 centre.11cars, water taxis and buses carry people along the city's canals (运河). However, they cause pollution,12to the water. English engineers Dick and Jem designed a solar-powered (太阳能的) water taxi. The water taxi13run for a day after being charged (充电).
Planes also cause air and noise pollution. Designing an environmentally friendly airplane is a real14. Some airplane companies have15to solve the problems. Swiss engineers have gone one step further. They developed a solar airplane. This airplane even tries to travel around the world.
