Even before there were people, there were cases of air pollution. There were dust storms(

Even before there were people, there were cases of air pollution. There were dust storms(沙尘暴). Volcanoes erupted, sending ash and poisonous gases into the atmosphere. When people appeared on the scene(登上历史舞台) and began their conquest of nature, they also began to pollute the air. They cleared land, which made possible even larger dust storms. They built cities, and the soot(煤烟) from their hearths(灶炉) filled the air. The Roman author Seneca wrote in A.D 61 of the “stink(臭味), soot and heavy air” of the imperial city. In 1257, the Queen of England was forced to move away from the city of Nottingham because the heavy smoke was unbearable. The industrial revolution brought even worse air pollution. Coal was burned to power factories and to heat homes. Soot, smoke, and sulfur dioxide(SO2) fill the air.

The good old days ? Not in the factory towns. But there were large rural areas unaffected by air pollution.

With increasing population, the entire world is becoming more urban. It is the huge cities that are most affected by air pollution. But rural areas are not unaffected. In the neighborhoods around smoky factories, there is evidence of increased rates of spontaneous abortion(自然流产) and of poor wool quality in sheep, decreased(减少) egg production and a high death rate in chickens.

Traffic police in Tokyo have to wear gas masks and take “oxygen breaks”-breathing occasionally from tanks of oxygen. Smog in Athens at times has forced factory closings and traffic restrictions. Acid rain in Canada is caused by air pollution in the United States, contributing to strained(紧张的) relationships between the two countries. Sydney, Rome, Tehran(德黑兰), Ankara, Mexico City, and most other major cities in the world have had frightening experiences of air pollution.

One of the two major types of smog-consisting of smoke, fog, sulfur dioxide, sulfuring acid(H2SO4), ash and soot – is called London smog. Indeed, the word smog is thought to have originated in England in 1905 as a contraction(缩略式) of the words “smoke” and “fog”.

Probably the worst case of smog in history started in London on Thursday, 4 December, 1952. A large cold air mass moved into the valley of the Thames River. A temperature inversion(倒转，逆反)placed a blanket of warm air over the cold air. With nightfall, a dense(浓厚的) fog and below-freezing temperatures caused the people of London to put coal into their small stoves. Millions of these fires(火炉) burned throughout the night, pouring sulfur dioxide and smoke into the air. The next day, Friday, the people continued to burn coal when the temperature remained below freezing. The factories added their smoke and chemical fumes(烟，气体) to the atmosphere.

Saturday was a day of darkness. For twenty miles around London, no light came through the smog. The air was cold and still. And the coal fires continued to burn throughout the weekend. On Monday, 8 December, more than one hundred people died of heart attacks while trying desperately(拼命地) to breathe. By the time a breeze(微风) cleared the air on Tuesday, 9 December, more than 4,000 deaths had been caused by the smog.

Soot and ash can be removed by electrostatic precipitators(静电吸尘器). Unfortunately, they use large amounts of electricity, and the electrical energy, which is hardly affordable for most of us, has to come from somewhere. Fly ash removed from the air has to be put on the land or water, although it could be used in some way.

The elimination(去除) of sulfur can be washed from finely(细微的) pulverized(粉末化) coal, the process is expensive. There are also processes for changing dirty coal into clean liquid and gaseous fuels. These processes may hold promise for the future, but they also too expensive to compete economically with other fuels at present. They also waste a part of the coal’s energy.

(   ) 45. What is the passage mainly talking about?

1. The type and form of pollution
2. The cause and effect of pollution
3. The situation and elimination of pollution
4. The concept and examples of pollution

(   ) 46. What can we infer from the first paragraph?

1. Human beings should not have begun their conquest of nature.
2. Human activities contribute more to pollution than natural disasters do.
3. Seneca and Queen of England were both over-sensitive to air pollution.
4. The industrial revolution was a disadvantage in terms of air pollution.

(   ) 47. With the example of “decreased egg production” in Paragraph 3, the author intends to _________.

1. explain why the world is becoming more urban.
2. indicate that heavy pollution also exists in rural areas.
3. Show that large cities are most affected by air pollution
4. prove smoky factories are more affected by air pollution.

(   ) 48. What is the right order about the 1952 London Smog?

1. A breeze cleared the air of London.
2. Thousands of people died
3. There was a day of darkness in London.
4. A large cold air mass caused a blanket of warm air over London.
5. London people made continuous fires from coal to keep warm.

A. d-e-c-b-a   B. c-e-d-a-b   C. d-c-e-b-a   D. c-d-e-a-b

(   ) 49. What does the author mainly want to say in the last two paragraph?

1. The technology to remove air pollution is only currently in development.
2. Society must be prepared to spend whatever it takes to eliminate air pollution.
3. Air pollution control is too costly to be achieved at the current time.
4. Pollution can be controlled using man-made scientific techniques.

(   ) 50. It can be inferred that when writing this article, the author was in a(n) _____ mood about the topic.

A. sympathetic           B. optimistic         C. desperate              D. concerned

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