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 (貫穿) 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 (運(yùn)動(dòng)感應(yīng)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 本文是一篇科教類閱讀,文章談及微波爐可以使人暖和,人們不必浪費(fèi)能量給墻壁和家具加熱.微波直接進(jìn)入人的皮膚使人溫暖,既安全又省能源.在未來,微波爐也許還有其它的用途.
解答 26-30 ABBAC
26.A.細(xì)節(jié)理解題.根據(jù)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.可知微波爐可以使人暖和,不必浪費(fèi)能量給墻壁和家具加熱.故選A.
27.B.細(xì)節(jié)理解題.根據(jù)文章第二段Low-power microwaves only penetrate (貫穿) the skin (low-power microwave penetration in a ham is about 0.2inches,for example) and with no negative effects.說明微波直接進(jìn)入人的皮膚使人溫暖,既安全又省能源.故選B.
28.B.細(xì)節(jié)理解題.根據(jù)文章第三段a satisfactory feeling of warmth occurs between 35and 50mw./sq.cm.可知溫馨滿意的感覺之間在35到50mw./sq.cm之間.故選B.
29.A.細(xì)節(jié)判斷題.根據(jù)文章第四段a motion detector (運(yùn)動(dòng)感應(yīng)器)would turn on the magnetron,可知一個(gè)運(yùn)動(dòng)探測(cè)器將打開磁控管.故選A.
30.C.主旨大意題.根據(jù)最后一自然段暗示了答案.也許微波加熱器將首先將被飼養(yǎng)牲畜的農(nóng)民使用,他們希望在冬季保護(hù)他們的羊羔.故選C.
點(diǎn)評(píng) 主旨大意題,就是指那些針對(duì)文章的主要內(nèi)容、主題、標(biāo)題或?qū)懽髂康乃O(shè)置的問題.這類題主要考查同學(xué)們?cè)诶斫馊牡幕A(chǔ)上運(yùn)用概括、判斷、歸納、推理等邏輯思維方法對(duì)文章進(jìn)行高度概括或總結(jié)的能力.要尋找這類文章的主旨大意就需要研究文章的主題句.