11．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 0.2inches，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，2459MHz magnetron （磁控管）．He found that a person will start to feel warmth at about 20kilowatts per square centimeter （mw．/sq．cm．）； a satisfactory feeling of warmth occurs between 35and 50mw．/sq．cm．By comparison，a person standing in noonday summer sun feels the amount of 85mw．/sq．cm．And a frozen meat pie in your microwave oven receives about 1000mw．/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.20mw．/sq．cm． B.40mw．/sq．cm．
C.60mw．/sq．cm． D.85mw．/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．
分析 本文是一篇科教类阅读，文章谈及微波炉可以使人暖和，人们不必浪费能量给墙壁和家具加热．微波直接进入人的皮肤使人温暖，既安全又省能源．在未来，微波炉也许还有其它的用途．
解答 26-30 ABBAC
26．A．细节理解题．根据文章第二段Using microwaves to directly heat owners of a room would save much of the energy wasted by heating walls and furniture．可知微波炉可以使人暖和，不必浪费能量给墙壁和家具加热．故选A．
27．B．细节理解题．根据文章第二段Low-power microwaves only penetrate （贯穿） the skin （low-power microwave penetration in a ham is about 0.2inches，for example） and with no negative effects．说明微波直接进入人的皮肤使人温暖，既安全又省能源．故选B．
28．B．细节理解题．根据文章第三段a satisfactory feeling of warmth occurs between 35and 50mw．/sq．cm．可知温馨满意的感觉之间在35到50mw．/sq．cm之间．故选B．
29．A．细节判断题．根据文章第四段a motion detector （运动感应器）would turn on the magnetron，可知一个运动探测器将打开磁控管．故选A．
30．C．主旨大意题．根据最后一自然段暗示了答案．也许微波加热器将首先将被饲养牲畜的农民使用，他们希望在冬季保护他们的羊羔．故选C．
点评 主旨大意题，就是指那些针对文章的主要内容、主题、标题或写作目的所设置的问题．这类题主要考查同学们在理解全文的基础上运用概括、判断、归纳、推理等逻辑思维方法对文章进行高度概括或总结的能力．要寻找这类文章的主旨大意就需要研究文章的主题句．
