Air pollution, global warming and overflowing landfills are the most serious environmental problems we are currently facing today.

The main cause of air pollution is the burning of fossil fuels.Other human activities,such as construction and the burning of waste,also contribute to air pollution.The effects on our health can be very serious.You can easily contribute to 【小题1】 (reduce) air pollution by using public transport.

Global warming 【小题2】 (cause) by the build-up of carbon dioxide and other pollutants in the atmosphere.These trap the sun’s heat and warm up the planet.Global warming has already caused 【小题3】 wide range of problems.

Landfills are used for waste disposal in many countries around the world.However,due 【小题4】 the amount of waste our lifestyles produce,these landfills are now reaching full capacity.When this happens,the chances of dangerous 【小题5】 (chemical) in the waste entering our water supply increase.The amount of waste in landfills in China 【小题6】 (rise) greatly over the last decade.The government is now trying to find alternative waste disposal methods.Apart from the three Rs (Reduce,Reuse and Recycle),some experts have begun advocating the fourth R — Responsibility.They believe 【小题7】although recycling waste is effective,the most effective way of solving the problem of overflowing landfills 【小题8】 (be) to encourage people 【小题9】 (take) responsibility for reducing the waste they produce 【小题10】 (they).

A new study looks at air pollution and its effects on premature deaths in the United States. Premature deaths【小题1】 (define) as those that take place before the average age of death.

Researchers found that half of all such deaths related to air pollution【小题2】 (result) from pollution that came from another state. The study is the first 【小题3】(examine) how pollution crossing state lines affects early deaths .

Worldwide, an【小题4】(estimate) 4.2 million premature deaths are linked to outdoor air pollution. Most of those deaths are from heart disease, stroke and lung disease, as well as acute breathing infections in children.

Efforts to deal with outdoor air pollution have【小题5】(large) centered on relationships between local sources of pollution and local air quality.【小题6】   Barrett and other researchers found that, in the United States, cross-state pollution is a major concern.

The computer model looked at the atmospheric chemistry processes and weather conditions over【小题7】11-year period. The researchers then examined how each of the lower 48 states affects pollution and people's health in every other state.

The team found electric power plants【小题8】release sulfur dioxide (二氧化硫) were the biggest【小题9】(contribute) to deaths related to pollution from other states. In 2005, sulfur dioxide from power plants was involved【小题10】75 percent of cases of premature deaths from out-of-state pollutants.

The Great Barrier Reef is one of Earth’s greatest 【小题1】 (nature) wonders. It’s the largest system of coral reefs in the world. The colorful underwater habitat provides food and shelter for many sea animals. But in 2018, scientists flying over the reef 【小题2】 (shock) by what they saw.

“Where you expected 【小题3】 (see) colorful healthy corals, what you saw was just white,” says scientist Mark Eakin. What the scientists saw is a condition called coral bleaching. It’s a warning sign that the reef is 【小题4】 serious trouble. Experts say 【小题5】 is rising ocean temperatures that are mostly to blame. Coral reefs look like plants, but they’re actually tiny animals that live together in huge groups. Corals get their nutrients from tiny plant-like living things called algae. The algae live inside corals and give them their color. But when the ocean gets too warm, corals release the algae. As 【小题6】 result, the corals get bleached white. Scientists say that bleaching is becoming more widespread as oceans get 【小题7】 (warm). Some corals can recover from bleaching as the water 【小题8】 (cool) in winter, but that is getting less likely as winter ocean temperatures rise too.

Reefs worldwide suffer from【小题9】 (pollute), overfishing, and other dangers, 【小题10】 scientists say climate change is the biggest threat. They predict that nearly 90 percent of all reefs will disappear by 2050.