铁丝在空气中灼热发红，但不能燃烧，而在纯氧中却能燃烧，这一事实与下列哪一因素关系
题型：选择题
问题：
铁丝在空气中灼热发红，但不能燃烧，而在纯氧中却能燃烧，这一事实与下列哪一因素关系最密切
A．铁丝的表面积
B．氧气的浓度
C．燃烧区的温度
D．铁的颜色
题型：选择题
阅读理解
The fridge is considered a necessity. It has been so since the 1960s when packaged food first
appeared with the label:"store in the refrigerator".
In my fridgeless Fifties childhood, I was fed well and healthily. The milkman came daily, the grocer, the butcher, the baker, and the ice-cream man delivered two or three times a week. The Sunday meat would
last until Wednesday and surplus (剩余) bread and milk became all kinds of cakes. Nothing was wasted,
and we were never troubled by rotten food. Thirty years on, food deliveries have ceased, fresh vegetables are almost unobtainable in the country.
The invention of the fridge contributed comparatively little to the art of food preservation. A vast way of well-tried techniques already existed -natural cooling, drying, smoking, salting, sugaring, bottling….
What refrigeration did promote was marketing-marketing hardware and electricity, marketing soft
drinks, marketing dead bodies of animals around the globe in search of a good price.
Consequently, most of the world's fridges are to be found, not in the tropics where they might prove
useful, but in the wealthy countries with mild temperatures where they are climatically almost unnecessary. Every winter, millions of fridges hum(嗡嗡响) away continuously, and at vast expense, busily maintaining
an artificially-coo1ed space inside an artificially-heated hous
e -while outside, nature provides the desired
temperature free of charge.The fridge's effect upon the environment has been evident, while its contribution to human happiness has been insignificant. If you don't believe me, try it yourself, invest in a food cabinet
and turn off your fridge next winter. You may miss the hamburgers, but at least you'll get rid of that terrible hum.
1. The statement "In my bridgeless Fifties childhood, I was fed well and healthily." in Para. 2 suggests
that .
A. the author was well-fed and healthy even without a fridge in his fifties
B. the author was not accustomed to use fridges even in his fifties
C. there was no fridge in the author's home in the 1950s
D. the fridge was in its early stage of development in the 1950s
2. Why does the author say that nothing was wasted before the invention of fridges?
A. People would not buy more food than was necessary.
B. Food was delivered to people two or three times a week.
C. Food was sold fresh and did not get rotten easily.
D. People had effective ways to preserve their food.
3. Who benefited the least from fridges according to the author?
A. Inventors.
B. Consumers.
C. Manufacturers.
D. Traveling salesmen.
4. Which of the following phrases in the fifth paragraph indicates the fridge's negative effect on the
environment?
A."Hum away continuously".
B."Climatically almost unnecessary".
C. "Artificially-cooled space".
D."With mild temperatures".
5. What is the author's overall attitude toward fridges?
A. Neutral.
B. Critical.
C. Objective
D. Compromising.