Solar cookers, or ovens, have been used for centuries. A Swiss scientist made the first solar oven in 1767. Today, people are using solar cookers in many countries around the world. People use solar ovens to cook food and to heat drinking water to kill bacteria and other harmful organisms.
There are three kinds of solar ovens. The first is a box cooker. It is designed with a special wall that shines or reflects sunlight into the box. Heat gets trapped under a piece of glass or plastic covering the top of the cooker. A box oven is effective for slow cooking of large amounts of food.
The second kind of solar oven is a panel cooker. It includes several flat walls, or panels, that directly reflect the sun’s light onto the food. The food is inside a separate container of plastic or glass that traps heat energy. People can build panel cookers quickly and with very few supplies. They do not cost much. In Kenya, for example, panel cookers are being manufactured for just two dollars.
The third kind of solar oven is a parabolic cooker. It has rounded walls that aim sunlight directly into the bottom of the oven. Food cooks quickly in parabolic ovens. However, these cookers are hard to make. They must be re-aimed often to follow the sun. Parabolic cookers can also cause burns and eye injuries if they are not used correctly.
Questions 33 to 35 are based on the passage you have just heard.
33. Which of the following is NOT a function of solar ovens?
34. What kind of oven is effective for slow cooking of a lot of food?
35. Which is the best title for this passage?
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