1 . The rainforests are alive with the sound of animals. Besides the pleasure of the din (喧嚣), it is also useful to ecologists. If you want to measure the biodiversity of a piece of land, listening out for animal calls is much easier than looking for tracks in the undergrowth. But such “bioacoustic (生物声音的) analysis” is still time-consuming, and it requires an expert pair of ears.

In a paper published on October 17th in Nature Communications, a group of researchers led by Jörg Müller, an ecologist at the University of Würzburg, describe a better way: have a computer do the job. Smartphone apps already exist that will identify birds, bats or mammals simply by listening to the sounds they make. Their idea was to apply the principle to conservation work.

The researchers took recordings from across 43 sites in the Ecuadorean rainforest. Some sites were relatively uncultivated, old-growth forests. Others were areas that had recently been cleared for grazing or cacao planting. And some had been cleared but then abandoned, allowing the forest to regrow. Sound recordings were taken four times every hour, over two weeks. The various calls were identified manually by an expert, and then used to construct a list of the species present. As expected, the longer the land had been free from agricultural activity, the greater the biodiversity it hosted.

Then it was the computer’s turn. The researchers fed their recordings to artificial-intelligence models that had been trained, using sound samples from elsewhere in Ecuador, to identify 75 bird species from their calls. “We found that the AI tools could identify the sounds as well as the experts,” says Dr Müller.

Of course, not everything in a rainforest makes a noise. Dr Müller and his colleagues used light-traps to catch night-flying insects, and DNA analysis to identify them. To their relief, they found that the diversity of noisy animals was a reliable proxy for the diversity of the quieter ones.

The results may have application outside ecology departments, too. Under pressure from their customers, firms such as L’Oreal, a make-up company, and Shell, an oil firm, have been spending money on forest restoration projects around the world. Dr Müller hopes that an automated approach to checking on the results could help monitor such efforts, and give a standardised way to measure whether they are working as well as their sponsors say.

3 . While riding hard on a bike, do you feel like you are saving the planet? Or do you just feel out of breath? In fact, cycling is now considered one of the best weapons mankind can use in the fight against climate change.

The United Nations General Assembly passed a resolution (决议) in March supporting bicycles as a tool for dealing with climate change. The resolution calls on member states to “add the bicycle to public transportation, in the city and countryside, in developing and developed countries”, with all 193 members of the UN agreeing upon the resolution.

The decision has received positive comments from different groups in support of cycling and the environmental awareness internationally. “It’s an important step toward the recognition of cycling as an important means of transport,” said the European Cyclists Federation.

The resolution from the UN comes at a time when climate change has returned to the center of the world’s attention. On February 28, the UN published a new report assessing (评估) recent climate change trends (趋势). The report warns that the world’s average temperature will rise by 1.5 C above pre-industrial levels (1850-1900), with more than 40% of the world’s population being “easily affected” to these temperature changes.

Cycling is an environmentally friendly means of transport. Choosing to take a bike instead of a car just once a day can reduce a person’s carbon emission (碳排放) from transport by 67 percent, according to a research by the University of Oxford. The research also found that cyclists produced 84 percent lower CO 2 emissions from all daily travel than non-cyclists.

Cycling has grown in popularity as people who take public transport to work wish to stay away from crowded public transport and also like taking any opportunity to exercise. Cycling culture has been further encouraged with the influence of COVID-19. In May 2020, bike sales in Spain increased 22 times compared with 2019. In London, large parts of the city are being closed off to cars so that people can walk and cycle safely.

More importantly, the resolution focuses on bike-sharing services, which could be seen as recognition of China’s bike-sharing success, noted CGTN. China has some of the largest bike-sharing systems in the world. This means of transport that produces zero emissions reduces the amount of CO2 sent out into the atmosphere (大气层) by 4.8 million tons every year, according to a 2020 report from the World Resources Institute.

4 . The world itself is becoming much smaller by using modern traffic and modern communication means. Life today is much easier than it was hundreds of years ago, but it has brought new problems. One of the biggest problems is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, smell it, drink it and even hear it.

Man has been polluting the earth. The more people, the more pollution. Many years ago, the problem was not so serious because there were not so many people. When the land was used up or the river was dirty in one place, man moved to another place. But this is no longer true. Man is now slowly polluting the whole world.

Air pollution is still the most serious. It’s bad for all living things in the world, but it is not the only one kind of pollution. Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us angry more easily.

Many countries are making rules to fight pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air. Pollution by S02 is now the most dangerous kind of air pollution. It is caused by heavy traffic. We are sure that if there are fewer people driving, there will be less air pollution.

The earth is our home. We must take care of it. That means keeping the land, water and air clean. And we must care about the rise in pollution at the same time.

I won't forget the Earthquake for the rest of life.When it strikes, I was alone sleeping. Suddenly I felt my bed shaking. I jumped out of it, and I couldn't stand up because of the whole building seemed like it was moving back and forth. I was so scaring and felt hopeless. I felt myself very closely to God. And I thought that I was going to die. Seconds late the quake stopped and I rushed outside. But the scene shocked me to died.The high buildings beside mine had collapsed to the ground. I suffered for quite the long time after that. I was in great pain. Now I'm feeling more better and I think I've walked out the shadow of it and found the strength to move on.

10 . Most people know something about the greenhouse effect. Factories send gasses such as carbon dioxide, or CO₂, into the atmosphere, the air around the earth. In the past, this wasn’t a problem because trees absorbed the CO₂. But now people in many countries are cutting down billions of trees all around the world. At the same time, factories are sending more CO₂ into the atmosphere. It’s difficult to believe, but factories put billions of tons of CO₂ into the atmosphere every year. One ton is over 2000 pounds, so it is a lot of pollution. There is too much CO₂ and there aren’t enough trees, so the world is getting warmer. In other words, we have a greenhouse effect. This is terrible for the environment.

What can we do about this? Firsts we can stop using so much coal and oil. We can learn to use different kinds of energy: the sun, wind, steam from volcanoes，and heat from inside the earth. Second, instead of cutting down trees, we should plant more trees. One tree can absorb ten pounds of carbon dioxide every year.

The trees are good for the earth’s atmosphere and for Guatemala (拉丁美洲国家危地马拉).In small towns and villages in Guatemala, most women are poor and have hard lives. Trees help them in three ways. First, the Connecticut factories pay them to plant the trees. Their pay is com, not money. The com is good for their children. Second, these women know a lot about their environment. They know where to plant when to plant, and what kinds of trees to plant. For example，they plant many fruit trees. The fruit gives them vitamins for their families^’ s diets. Other trees are good for firewood. In a few years, the women won’t spend so much time looking for firewood. Third, all these trees are good for the soil. Now rain can’t wash the soil down from the mountains so easily.

This plan isn’t enough to stop the greenhouse effect. However, it’s a start. The woman of Guatemala are helping themselves and helping their environment.