We went to Tibet to     1     Tibetan antelopes with Zhaxi as our guide.     2    , on the plain in front of us, we saw a herd of antelopes move slowly across the green grass. These beautiful animals     3     me of their danger because they are being hunted     4     for their valuable fur. Especially in the 1980s and 1990s, their population     5     by more than 50 percent. To save this species from     6    , the Chinese government placed it under national protection. Zhaxi and other volunteers watched over the antelopes day and night and bridges and gates were added to keep them     7    . These measures were     8     and the antelope population has recovered. However, the government doesn’t intend to stop the protection programmes, since the     9     to the Tibetan antelope haven’t disappeared. Only when we learn to exist in     10     with nature can we stop being a threat to wildlife and to our planet.

Herds of Tibetan antelopes used to live on the     1     of Tibet, Xinjiang and Qinghai. But today, they face a serious     2     from hunters. These large animals are being killed illegally for their body parts that are considered valuable. In order to save them, the government has created     3     where they can live in peace and safety. However, the     4     on them will continue as long as interest in buying antelope products     5    . To achieve harmony between humans and animals, the world must protect these beautiful creatures.

Air pollution triggers (引发)more heart attacks than using cocaine and poses as high a risk of sparking a heart attack as alcohol, coffee and physical exertion, scientists said on Thursday. Anger, marijuana (大麻)use and chest or respiratory (与呼吸有关的)     1     can also trigger heart attacks to different extents, the researchers said, but air pollution,       2     in heavy traffic, is the major cause.

The findings, published in The Lancet journal, suggest population-wide       3     like polluted air should be taken more       4     when looking at heart risks, and should be put into context besides higher but relatively rarer risks like drug use. Tim Nawrot of Hasselt University in Belgium, who led the study, said he hoped his findings would also encourage doctors to think more often about population level risks.

Nawrot’s team combined data from thirty-six       5     studies and calculated the relative risk posed by a series of heart attack triggers and their population-attributable fraction (PAF)—in other words the proportion of total heart attacks estimated to have been caused by each trigger. “Of the triggers for heart attack studied, cocaine is the most likely to trigger an event in an individual, but traffic has the greatest population effect as more people are       6     to it,” the researchers wrote. “PAFs give a measure of how much disease would be avoided if the risk was no longer       7    . ”

A report published late last year found that air pollution in many major cities in Asia exceeds the WHO’s air quality guidelines and that poisonous       8     of pollutants result in more than 530,000 earlier deaths a year. While       9     smoking was not included in this study, Nawrot said the effects of secondhand smoke were likely to be similar to that of outdoor air pollution, and noted previous research found that bans on smoking in public places have       10     reduced heart attack rates.

Standing in line at the grocery store last week, I watched the woman in front of me buy a tube of toothpaste. As the clerk placed her     1    in a plastic bag, I couldn’t help wondering how long it would take for that bag to end up in the trash. Then I noticed the big purse the woman was carrying and wondered why she had needed a plastic bag at all.

People have come to rely on plastic bags as everything from shopping bags for groceries to     2    bags. Although plastic bags can be recycled, only about one percent of those used in the United States are. Instead, after helping people     3    items from one place to another, most are thrown away. They end up in landfills, where it can take a plastic bag up to a thousand years to decay. Some bags end up     4    in the environment, sticking to trees and fences, blocking rivers and oceans, or floating along city sidewalks.

Plastic bags harm the environment in several ways. First, they break     5     into particles that pollute our soil and water. Because most plastic bags are made of polyethylene, a product derived from crude oil(原油)or natural gas, they waste     6    resources. Plastic bags can also harm animals. Scientists estimate that more than one million sea animals, including whales, seabirds, and turtles, die each year from     7    or becoming stranded in plastic.

People all over the world are starting to recognize the problems associated with plastic bags. Countries such as China, South Africa, Switzerland, and Uganda are taking action and banning the bags. Other nations, including Italy and Ireland, have been trying to     8    the use of plastic bags by     9    them. In the United States more and more communities are ridding themselves of plastic bags. Now more and more people are also purchasing inexpensive,     10    bags and using them whenever they shop. If we all take this simple step, we can be a part of a “green” revolution.

The pollution of the earth’s soil and water has become an issue of great concern. Until recently, most of that     1     has focused on the land     2     of the planet, where pollution directly affects people in their daily lives. Now, however, we have begun to realize that marine (海洋的) pollution is     3     important. According to S.A. Patin, marine pollution is the condition that results when people introduce into the seas substances harmful to life, health, resources, activities, or     4    .

Marine pollution is far from new. For over a million years, people have thought of the sea as a     5     place to throw their garbage. And it is true that the sea has a great capacity for absorbing organic wastes. Some of these wastes are eaten directly by the larger fishes. Others quickly     6     into a kind of organic soup that provides food to     7     species of single-celled plant and animal life.

As civilizations grew, more different pollutants were dumped into the seas. Still, this pollution did not really threaten the marine environment. The seas seemed     8     of coping with anything that people could throw at them. This situation changed, however, when suddenly factories began dumping enormous quantities of materials into the seas. Especially in some coastal areas near large cities, ocean pollution began to     9     marine life. For the first time, the oceans began to fail in their ability to     10     humanity’s waste.