Question

18．Microwaves may be great at warming up food，but what about warming people？
    Using microwaves to directly heat owners of a room would save much of the energy wasted by heating walls and furniture．And despite popular ideas about microwaves，this technique would be safe，according to Charles R．Burlier of the Microwave Research Center in Marlborough，New Hampshire．Low-power microwaves only penetrate （贯穿） the skin （low-power microwave penetration in a ham is about 0.2 inches，for example） and with no negative effects．
    To test this idea，Buffler subjected himself to microwaves in a special room using a standard 500-watt，2459 MHz magnetron （磁控管）．He found that a person will start to feel warmth at about 20 milliwatts per square centimeter （mw．/sq．cm．）； a satisfactory feeling of warmth occurs between 35 and 50mw．/sq．cm．By comparison，a person standing in noonday summer sun feels the amount of 85 mw．/sq．cm．And a frozen meat pie in your microwave oven receives about 1000 mw．/sq．cm．
    In houses of the future，each room could be provided with its own magnetron，says Buffler．When you stepped into the living room，for example，a motion detector （运动感应器）would turn on the magnetron，filling the room with low-power microwaves．In the same way that a microwave oven heats up a hamburger，but not the plate it's on，you would feel warmth from the microwaves without changing the temperature of your coffee table．（You could，however，make your favorite easy chair even more comfortable by treating it with a radiation-absorbing chemical．）
    While it might be some time before homeowners are comfortable enough with the idea to set up whole-body microwave heaters in houses，Buffler says microwaves may attract livestock（家畜） farmers．Lambs that are born outdoors in winter，for example，are frequently lost to cold．Microwaves could warm the lambs safely and quickly．
26．Which of the following can tell the main idea of the passage？A
A．A new heating system．
B．A new microwave oven．
C．A popular technique．
D．The magnetron．
27．According to Paragraph 2，which of the following does not describe the characteristics of a microwave heater？B
A．It directly heats people in a room．
B．It heats walls and furniture in a room．
C．It is safe．
D．It saves energy．
28．The test conducted by Buffler shows that when a person feels comfortable warmth，he receives aboutB．
A.20 mw．/sq．cm
B.40 mw．/sq．cm
C.60 mw．/sq．cm
D.85 mw．/sq．cm
29．According to Paragraph 4，which of the following fills the room with low-power microwaves？A
A．The magnetron
B．The motion detector．
C．The microwave oven
D．The radiation-absorbing chemical．
30．Which of the following statements about microwave heaters would Buffler most probably agree with？C
A．Microwave heaters will soon be widely used by homeowners．
B．Microwave heaters sometimes make people feel uncomfortable．
C．Perhaps microwave heaters will be first used by livestock farmers，who wish to protect their lambs in winter．
D．Microwave heaters cannot be accepted by the public because they are somewhat unsafe．

Answer 1

分析 本文属于说明文阅读，作者通过这篇文章主要向我们描述了一种新型供暖系统微波加热器，安全便捷，损耗小，不加热墙壁和家具，直接加热房间的人．

解答 26．A．推理判断题．根据第二段Using microwaves to directly heat owners of a room would save much of the energy wasted by heating walls and furniture可知文章讲的是一种新型供暖系统；故选A．
27．B．细节理解题．根据第二段Using microwaves to directly heat owners of a room would save much of the energy wasted by heating walls and furniture可知微波加热器不加热墙壁和家具，直接加热房间的人；故选B．
28．B．细节理解题．根据第三段He found that a person will start to feel warmth at about 20 milliwatts per square centimeter （mw．/sq．cm．）； a satisfactory feeling of warmth occurs between 35 and 50mw．/sq．cm可知40毫瓦/平方厘米时一个人感到舒适温暖；故选B．
29．A．细节理解题．根据第四段When you stepped into the living room，for example，a motion detector （运动感应器）would turn on the magnetron，filling the room with low-power microwaves可知磁控使房间充满了低功率微波；故选A．
30．C．推理判断题．根据最后一段Buffler says microwaves may attract livestock（家畜） farmers．Lambs that are born outdoors in winter，for example，are frequently lost to cold．Microwaves could warm the lambs safely and quickly可知微波炉将首先被家畜饲养者使用，他们希望在冬天保护他们的羊羔；故选C．

点评 考察学生的细节理解和推理判断能力，做细节理解题时一定要找到文章中的原句，和题干进行比较，再做出正确的选择．在做推理判断题不要以个人的主观想象代替文章的事实，要根据文章事实进行合乎逻辑的推理判断．