The fast shift toward clean energy technologies means global greenhouse gas emissions may fall in 2024. Recent analysis from the International Energy Agency (IEA), based on the public     1     of governments, suggests emissions may in fact have peaked last year. The finding is supported by analysis from Climate Analytics, which found a 70% chance of emissions falling from 2024 if the current growing     2     in clean technologies continues.

A growing number of major economies have already passed their period of    3     emissions, including the United States, the European Union, the United Kingdom and Japan. Compared with them, China now is the most     4    in emitting greenhouse gases, contributing 31% of the global total last year. But explosive growth in clean energy    5    means China’s emissions are set not only to fall in 2024, but to go into structural    6    . What’s more, China is currently    7     a boom in clean energy production and a historic growth of renewable energy — especially solar. Similarly,     8     is expected for batteries and electric vehicles.

A peak in global emissions is cause for optimism — but it is far from     9     the problem. More greenhouse gases will still be    10     in the atmosphere and drive severe warming, until we bring the emissions as close to zero as possible.

“When a snow leopard follows its prey (猎物) among the mountain walls, it moves... softly, slowly,” explains Indian biologist Raghunandan, who has studied animals for years. “If it knocks a stone loose, it will     1     out a foot to stop it from falling and making noise.” One might be moving right now,     2     silent, maybe close by. But where?

Best known for its     3     coat and long distinctive tail, the snow leopard is one of the world’s most secretive animals. These big cats can only be found high in the remote,     4     regions of Central Asia. For this reason, and because they hunt     5     at night, they are very rarely seen.

Snow leopards have been officially protected since 1975, but enforcing this law has proven difficult. Many continue to be killed for their fur and body parts, which are     6     a fortune on the black market. In recent years, though, conflict with local herders (牧人) has also led to a number of snow leopard deaths. This is because the big cats kill the herders’ animals, and drag the bodies away high up in the mountains to eat. Thus, the herders’ animals are in danger of snow leopard attacks, which can push those herders into desperate poverty. To address this problem, local religious leaders have called for an end to snow leopard killings, saying that these wild animals have the     7     to exist peacefully. They’ve also tried to     8     people that it is of great importance to protect those big cats.

As a result of these pressures, the     9     snow leopard population is estimated at only 4,000 to 7,000, and some fear that the actual number may already have dropped below 3,500．The only way to     10     this trend and bring these cats back from their threatened status, say conservationists, is to make them more valuable alive than dead.

Peru, a country in South America, used to be the centre of the     1     ancient Inca Empire. Later Spain    2     it in the 16th century, so Spanish is its main    3     language. As a visitor, there are many package tours for you to choose from. In the Amazon Rainforest Tour you’ll live in the middle of the forest and enjoy the plants and animals    4     the rainforest. The Machu Picchu Tour will take you on amazing    5     to Machu Picchu. After reaching your destination, you will     6     by this ancient city, especially its dry stone method of building. The Cusco Tour will help you enjoy the Spanish culture with its    7     while the Lake Titicaca Tour will provide you with a chance to stay with a local Uros family whose home    8     water plants.

All Change in Curitiba!

Like many other major world cities, Curitiba in southern Brazil has had to deal with issues such as pollution, poverty, and limited public funding. However, the architect and three-times mayor of the city, Jaime Lerner, has introduced some     1     solutions.

As part of his ‘Master Plan’, Lerner hoped to make the city more environmentally friendly. He initiated a recycling scheme. In return for delivering recyclable rubbish to specified     2     points, residents receive a bag of vegetables or bus tickets. As a result, Curitiba now has one of the highest recycling rates in the world. Lerner also ordered the     3     of 26 urban parks. As well as preventing pollution, these control flooding.

Lerner did not win over all the city’s residents immediately, however. When his plans to     4     part of the centre were passed, local businesses were up in arms, fearing a reduction in profits. Realising he needed to act quickly, Lerner had the     5     of six blocks completed within three days. When a group of motorists attempted to drive through the new pedestrian area, Lerner arranged for local primary schools to hold a painting workshop on the streets. The drivers were forced to turn back. Luckily for Lerner, this rebellion was     6    . The increase in profit rapidly persuaded shop owners to change their minds.

Lerner’s determination helped     7     the Curitiba of today. The average income per capita has risen from a level that was below the Brazilian average in the 1970s to 66% above the average, and surveys indicate high levels of resident satisfaction.

So, is it all just one big success story? In some respects, Curitiba may have been too successful for its own    8    . People and businesses have come to the city, which now has more than 1.8 million residents. This has put the city under enormous stress. Forty years ago, buses transported 54,000 passengers a day. Now the number is 2.3 million. According to some experts, the transport system has reached its     9     efficiency capacity. Following a rise in complaints about the noisy and     10     buses, the service is in decline.

Haul of Fossil Fish Pushes Back the Origin of Teeth and Jaws

Our teeth and jaws are incredibly ancient. They’re older than dinosaurs, older than arms and legs, older than trees adaptations that paleontologists (古生物学家) have     1     to our distant, fishy relatives that thrived in the seas around 425 million years ago. But a collection of carefully-preserved vertebrates (脊椎动物) found in China has     2     a new date for the earliest record of jaws and teeth. The early vertebrates include some of the earliest fish, one of the earliest relatives of sharks, and, at about 436 million years old, the most ancient     3     yet found of fish with teeth and jaws.

Researchers have disagreed about     4     when the earliest bites evolved. Molecular (分子的) studies based upon estimations of genetic changes have     5     that the first jaws and teeth evolved about 450 million years ago. Until now, the oldest fossil of jawed vertebrates — or gnathostomes —     6     to about 425 million years ago, a significant gap. As Institute of Vertebrate Paleontology and Paleoanthropology researcher Min Zhu and his colleagues describe in a series of Nature papers published today, the new     7    from South China sit in the middle of this gap and offer a startling look at a critical moment in evolutionary history.

Zhu and coauthors note in their research, the fish they uncovered were small and had     8     bones. That means these fish were generally     9     to become fossils except in truly outstanding circumstances where they could be buried quickly and shielded from scavengers (食腐动物) that would otherwise eat them. That an exceptional stroke of luck was required to preserve such fish likely explains the difference between the molecular     10     and fossil record.

For the first time, scientists have mapped the whole surface of Titan, the largest moon around Saturn. The map confirms existing data showing that Titan has many Earth-like     1     that might be able to support life.

The data was collected by Cassini, a spacecraft operated by the U.S. space agency NASA. The spacecraft studied Saturn and its moons from 2004 to 2017. Astronomers used images and radar measurements from Cassini to create the     2     map of Titan.

The map shows Titan as a mixture of flat plains, hills and mountains, windblown sand areas, valleys and lakes. The mapping operation is     3     in a report published in Nature Astronomy.

Rosaly Lopes led the project. She is a planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. Lopes told the publication that the many similarities between Earth and Titan make the Saturn moon a great choice for     4     exploration.

“Titan has an atmosphere like Earth's. It has wind; it has rain; it has mountains,” Lopes said.

Titan is the only planet in our solar system besides Earth to have known     5     of liquid on its surface. But Titan's seas and lakes are filled with liquid methane (甲烷) rather than water.

At cold temperatures, methane goes through similar     6     as rain does on Earth. It falls to the surface across the planet to form rivers and lakes and can then evaporate (挥发) to form clouds again.

The map found that nearly two-thirds of Titan's surface is made up of flat plains, Nature reported. About 17 percent is covered in sandy hills     7     by the wind, mostly around the equator.

Unlike Earth, Titan's sand is made up of carbon, hydrogen, nitrogen and oxygen. Around 14 percent of the surface is considered hilly or mountainous. Seas and lakes filled with liquid methane cover a(n)     8     1.5 percent of Titan. The liquid exists mainly closer to the planet's poles, while the equatorial areas remain drier.

Rosaly Lopes says organic materials --- those containing carbon --- in Titan's atmosphere are     9     for the growth of living organisms. “Organics are very important for the possibility of lifeon Titan, which many of us think likely would have     10     in the liquid water ocean under Titan's icy crust (硬的表面),”she said.