Each one of us shares this planet with about 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 also noisy. This is a serious problem in many cities.3inventors are coming up with creative ideas to try to reduce the air pollution and noise.
In many cities around the world, motorcycles are very4. 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 than5. Yet air pollution is a growing problem. In large cities, people complain 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 is6pollution. It's also quiet and fast. This makes it a good choice for getting around a city.
The Italian city of Venice is a city with only a few roads. There are no cars in the city centre.7cars, water taxis and buses carry people along the city's canals. However, they cause pollution,8to the water. English engineers Dick and Jem designed a solar powered(太阳能的) water taxi. The water taxi can run for a day after being charged.
Planes also cause air and noise pollution. Designing an environmentally-friendly airplane is a real9. Some airplane companies have10to 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 kilometres from Arizona to Texas in America.
