Last night’s meteor shower (流星雨) left many people in the community dissatisfied and demanding answers.   According to Gabe Rothschild, Emerald Valley’s mayor, people gathered in the suburbs of the city, carrying heavy telescopes, expecting to watch the brightly burning meteors passing through the sky. What they found instead was a sky so brightened by the city’s lights that it darkened the light of the meteors passing overhead.

“My family was so frustrated, ” admitted town resident Duane Cosby, “We wanted to make this an unforgettable family outing, but it turned out to be a huge disappointment. ”

Astronomers-scientists who study stars and planets-have been complaining about this problem for decades.   They say that light pollution prevents them from seeing objects in the sky that they could see quite easily in the past.   They call on people and the government to take measures to fight against it.

There is yet a population besides professional and amateur star observers that suffers even more from light pollution.   This population consists of birds, bats, frogs, snakes, etc.   For example, outdoor lighting badly affects migrating (迁徙) birds.   According to the International Dark-Sky Association, “100 million birds a year throughout North America die in crashes with lighted buildings and towers. ”

Countless more animal casualties (伤亡) result from the use of artificial lighting.   Clearly, people enjoy the benefits of lighting their evenings.   But some scientists think it can be harmful for humans, too. They worry that exposure to light while sleeping can increase a person’s chances of getting cancer.

Emerald Valley is only one community that is becoming aware of the negative effects of light pollution.   For years, Flagstaff, Arizona, has enforced lighting regulations in its city in order to help astronomers at the Lowell Observatory with a good observation condition.   Similar efforts have been made worldwide, and a movement is under way to remind us to turn off lights when we are not using them, so that other creatures can share the night.

The government of Singapore has created a highly developed system that turns wastewater into drinking water. The system involves a network of tunnels and high technology treatment centers.

The system helps reduce ocean pollution, as only a small amount of the treated water is sent into the sea. The United Nations estimates that 80 percent of the world’s wastewater flows back into the oceans without being treated or reused.

Singapore has few natural water sources. The island nation has long had to depend mostly on supplies from neighboring Malaysia.

Low Pei Chin, an expert, told reporters, “Singapore lacks natural resources, and it is limited in space, which is why we are always looking for ways to explore water sources and stretch our water supply. One major plan is to collect every drop and reuse endlessly.”

Parts of the water treatment center are underground. Wastewater enters the center through a 48- kilometer tunnel that is linked to sewers. The center contains a large system of steel pipes, tubes, tanks, cleaning systems and other machinery. It can treat up to 900 million liters of wastewater a day.

In one building, a network of air flow systems has been put in place to keep the air smelling as fresh as possible. Waste that arrives at the plant goes through a cleaning process before powerful pumps send it flowing to areas above ground for more treatment. There, the treated water receives additional cleaning. Bacteria and viruses are removed through highly developed cleaning processes and then disinfected with ultraviolet radiation (紫外线).

Singapore is also in the process of expanding its recycling system. The country will add another underground tunnel and a major water treatment center to serve the western half of the island. Officials expect work on the center to be completed by 2025. By the time the expansion is finished, Singapore will have spent about $7.4 billion on its water treatment systems.

Earth Hour is organized by the World Wide Fund for Nature. It's a big event usually at the end of March every year. On this evening, people “go dark”. 【小题1】

It's true that turning off lights for just one hour saves only a small amount of power.【小题2】On one level, joining in Earth Hour makes people think about the problem of climate change and what we can do in everyday life to protect nature.

But on another level, a large number of people’s acting together sends a powerful message to governments and companies. 【小题3】 They begin considering green issues when big decisions.

The logo(标识) of Earth Hour is “60+” .The number 60 is for the 60 minutes of Earth Hour. 【小题4】 In fact, people who join in Earth Hour say that taking part makes them want to do more for the environment.

【小题5】 Musicians give concerts by playing acoustic(原声的) instruments instead of electric ones, and using candles instead of electric lights. Celebrity chefs have created special recipes for families to prepare and eat by candlelight. Tree-planting sessions, group walks and runs are also among the options.