環(huán)球英語 — 233：Sweet Potato
Voice 1
Thank you for joining us for today’s Spotlight program. I’m Mike Proctor.
Voice 2
And I’m Liz Waid. Spotlight uses a special English method of broadcasting. It is easier for people to understand, no matter where in the world they live.
Voice 1
Every day people hear about another crisis in the world. Earth’s population continues growing every year. People have fewer and fewer resources to share. Some people around the world are not able to get enough food to eat. A growing population also produces more solid waste like plastic, and gas waste like carbon dioxide. So, the environment also suffers. Communities around the world need energy. Energy normally comes from oil and coal. But these natural resources will not last forever ... it can be frightening to think about the future of the earth.
Voice 2
But could people find the answer to all these problems in a simple plant? Some experts say yes! Today’s Spotlight is on this amazing plant – the sweet potato.
Voice 1
No matter where in the world you live, you have probably eaten a sweet potato. There are more than four hundred [400] different kinds of this root vegetable! And many countries around the world grow them. Sweet potatoes are often long with pointed ends. Their smooth skin can be white, yellow, orange, red, or purple. But the flesh, the inside of the sweet potato, is usually white, yellow or orange. They are also naturally very sweet. That is why they are called ‘sweet potatoes’!
Voice 2
Experts believe that the first sweet potatoes came from South America near the Andes Mountains. They were especially important to the people of Peru and Columbia. Scientists estimate that people have been eating the sweet potato since about ten thousand [10,000] years ago! They say it is the oldest vegetable!
Voice 1
Today sweet potatoes are the sixth [6th] largest food crop in the world. People all around the world eat them. And they are part of an every–day diet for many Asian and Latin American cultures. But China, Indonesia, Vietnam, Japan, India and Uganda produce most of the world’s sweet potatoes.
Voice 2
At the beginning of this program we told you that sweet potatoes could be the answer to many problems – problems like world hunger, growing energy demands, and environmental damage. These are real problems that affect the earth’s future. So, how can the sweet potato do all these things? What is so special about this vegetable?
Voice 1
Well, first, experts say that sweet potatoes can help improve the world hunger situation. They say that more people should grow sweet potatoes. That is because sweet potatoes are very good for you! They are full of nutrients. These substances keep a person’s body healthy. They contain many vitamins and a lot of fibre. And usually, the more colourful the sweet potato is, the more vitamins it contains! Sweet potatoes also contain antioxidants. Antioxidants prevent harmful chemicals from damaging healthy cells in a person’s body. The natural chemical substances in sweet potatoes can also help prevent joint pain.
Voice 2
People need more than just healthy food to improve world hunger. For example, honest and good governments, good communication, and good trade policies must be involved in improving a country’s hunger problem. But sweet potato crops can be a healthy and valuable food resource.
Voice 1
Second, sweet potatoes can reduce the amount of energy that people need. Sweet potatoes are usually easy to grow. They resist wind. And they do not need very much water. They grow well even without growth chemicals or fertilizer. And they produce many times more food than some traditional crops. One piece of land can produce a particular amount of rice. But that same land can produce in weight six [6] times more sweet potatoes than rice! Similarly, experts say that a hectare of sweet potatoes can feed more people than a hectare of cereal grains!
Voice 2
Sweet potatoes are also good at absorbing, or taking in, heat. As cities grow and expand, they experience an increase in outside temperature. In fact, the temperature inside a city can be up to six [6] degrees hotter than in the country. When it is hot, people may start using devices that blow cool air into their homes. This uses a large amount of energy. So, experts encourage people who live in the city to plant sweet potatoes on the tops of their buildings. Even just six [6] sweet potato plants can cover about twenty five [25] square meters in only a few months. And the plants absorb the heat of the city, and make the area cooler.
Voice 1
The third problem that sweet potatoes can help to solve is environmental damage. As you may know, plastic waste is a big problem for the environment. Pieces of plastic from cars, toys, machines, and more, appear in waste areas all over the world. Even a small, simple plastic carrying–bag can take one thousand [1,000] years to return to a natural substance. This is called biodegrading.
Voice 2
Well, experts say that people can make biodegradable plastic using sweet potatoes. That is, bacteria in the earth will be able to naturally break down, or biodegrade, this sweet potato plastic. And the plastic will also biodegrade much more quickly than normal plastic. People and businesses could use this sweet potato plastic in any place that they use normal plastic!
Voice 1
These are all good ideas about how to use sweet potatoes to improve life on earth. But sweet potatoes are not just useful on earth!
The U.S. space program, NASA, believes that sweet potatoes will be important for future space missions. Astronauts travel in space for long periods of time. And they need a lot of food on their space–ship. Well, sweet potatoes produce a large harvest in very limited space. And people can eat the whole plant – both the top leaves and the roots. This means less waste on the space–ship. And the sweet potato contains so many nutrients that it is perfect for space travel.
Voice 2
Sweet potatoes have a long history on the earth. And clearly, sweet potatoes could have an important part in the earth’s future. They can help reduce energy use and help keep the environment clean. And they can even be used in space! But, don’t forget that they also taste very good. If you can, eat a sweet potato today, and remember all the wonderful things it can do!
