2．佳句 （1）Pollution is, in fact, threatening our existence.
（2）Villagers are as a rule healthier than people who live in towns. One reason for this is that country air is fresher than the air in smoky cities.
（3）Most of the noise in the city comes from traffic, factories and construction sites.
（4）There is an increasingly loud voice from the public calling for firm action against pollution.
（5）Scientists have warned that unless effective solutions are worked out, the problem of pollution will eventually get out of hand.
（6）Many factories discharge enormous harmful chemicals into air and rivers every day.
（7）To kill insects, farmers use a large amount of insecticides so as to have a bumper harvest. As a result, they pollute the air, water and land.
（8）The gas from car engines is very poisonous. It is a main source of air pollution in cities.
（9）Deforestation result in the increase of global temperature and unpleasant change of climate.
（10）The earth is our home and we have the duty to take care of it for ourselves and for our later generation.
（11）Beijing now has become one of the most polluted cities in the world. Among the 10 cities with the worst air pollution in the world last year, Beijing was the third most polluted city.
（12）If the city had not plagued by poor quality air, the annual death rate in Beijing would have been 4 percent lower in past three years, according to the research done jointly by Beijing Medical University and Harvard University.
（13）Beijing consumes 2.8 million tons of coal each year, of which 75 percent are low-grade coal.
（14）To make room for those buildings, trees are being cut down, grass plots occupied. Cities look like nothing but grey concrete woods.
（15）Modern cities should be expanding with a certain percentage for green-plant areas.
（16）We must begin now to protect our only earth.
（17）Almost everything we use daily comes from the land directly or indirectly.
（18）But the limited land is decreasing at a surprising speed.
（19）The nature has given us so much, but looks at what we have done in return for its generosity.
（20）The ozone layer is our natural shield in the sky, but this shield is in great danger due to human activities. To protect the ozone layer is to protect us.
（21）Depleting the ozone layer allows more UV-B to reach the earth, which means more skin cancers, more eye cataracts（白内障），weakened immune systems, and reduced plant yield.
（22）The nature has been irritated, which results in the shortage of valuable resources, air pollution, countless acres of lands becoming deserts, etc.
（23）Fortunately, many countries have got to know the seriousness of the problem and take active measures to preserve the environment.
（24）We sincerely hope that all the people in the world will take part in the campaign and join hands to protect the nature.
（25）Besides, trees and lawns in our cities will in the long run help improve the local climate.
