Millions of people around the world cook their food over a smoky fire every day. It is often difficult to find wood for the fire. People who do not have wood must spend large amounts of money on cooking (36)_______. However, there is a much easier way to cook food using energy from the sun.

Solar cookers, or ovens, have been used for centuries. A (37)______ scientist made the first solar oven in seventeen sixty-seven. 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 (38)_______and other harmful (39)_______.

There are three kinds of solar ovens. The first is a box cooker. It is designed with a special wall that shines or (40)__________sunlight into the box. Heat gets trapped under a piece of glass or plastic covering the top of the cooker. A box oven is (41)_____ 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 (42)___________.they do not cost much. In Kenya, for example, panel cookers are being (43)______for just 2 dollars.

The third kind of solar oven is a parabolic cooker. (44)___________________________________________________________. However, these cookers are hard to make.

They must be re-aimed often to follow the sun. (45)_______________________________________________________________.

You can make solar ovens from boxes or heavy paper. They will not catch fire. Paper burns at two hundred thirty-two degrees Celsius. A solar cooker never gets that hot. (46)_________________________________________________________.

答案:
36. fuel
37. Swiss
38. bacteria
39. organisms
40. reflects
41. effective
42. supplies
43. manufactured

44. It has rounded walls that aim sunlight directly into the bottom of the oven. Food cooks quickly in parabolic ovens.

45. Parabolic cookers can also cause burns and eye injuries if they are not used correctly

46. Solar ovens cook food at low temperatures over long periods of time. This permits people to leave food to cook while they do other things.