（E）

  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 lots of money on cooking fuel. However, there is a much easier way to cook food using energy from the sun.

Solar cookers(太阳能炊具), or ovens(灶), 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(细菌) and other harmful organisms(有害的生物体).

There are three kinds of solar ovens. The first is a box cooker. It is designed with a special wall that shines or reflects(反射)sunlight into the box. Heat is trapped under a piece of glass or plastic covering the top of the cooker. A box oven is effective for slow cooking of lots of food. The second kind of solar oven is a panel(平板)cooker. It includes several flat walls, or panels, that directly reflect the sun’s light onto the food. The food is inside some containers 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(肯尼亚), for example, panel cookers are being made for just two dollars. The third kind of solar oven is a parabolic(像抛物线的)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 moved often to follow the sun. Parabolic cookers can also cause burns and eye injuries if they are not used correctly.

You can make solar ovens from boxes or heavy paper. They will not catch fire. Paper burns at 232℃. A solar cooker never gets so hot. 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.

72.Using energy from the sun can ____than using any other fuel for cooking food.

 A. bring down the price of fuel more quickly     B. a better choice

 C. be operated more easily                               D. produce more heat energy

73.Which of the following is not described about the solar cookers in the text?

A.           B.              C.            D.

74.We may learn from the text that the ways of cooking food are _____ in solar ovens.

 A. convenient              B. the same                  C.    different                D. comfortable

75.It takes much more time to use _____ than to cook food over a smoky fire. 

 A. a box cooker           B. a panel cooker           C. a parabolic cooker    D. solar cookers