A．the cover of it is heated by fire

　　B．the sides of the box are black

　　C．some heat can escape from the top

　　D．food takes up a small space in it

　　答案与解析：B　细节理解题。根据第一段第五句"The solar dryer works better if the sides of the box are black."可知应选B。

　　9．The surface where food is put should be ________.

　　A．dried by wind or air

　　B．painted with light color

　　C．made with small openings

　　D．made of glass or wire

　　答案与解析：C　细节理解题。根据第二段第二、三句"The surface on which the food is placed should permit air to enter from below and pass through to the food. A surface made of wires with small square openings works very well."可知，盒子的底部应该通风，所以要有洞。

　　10．We can learn from the text that ________.

　　A．it's easier to dry fruits than other food

　　B．food dried by a direct dryer looks black

　　C．it takes long to dry food with sunshine

　　D．solar drying is a healthy way to dry food

　　答案与解析：D　推理判断题。根据最后一段最后一句"It is also healthy because nutrients such as vitamin C are kept in the food."可知，利用太阳能烘干食物是一种健康的方法。

　　11．Which of the following would be the best title for the text?

　　A．How to Keep Food

　　B．How to Dry Food

C．The Direct Dryer