3 . One of Prague’s most famous sights, the Orloj, the third oldest clock in the world, has been stopped. It is set to undergo months of restoration (修复)that will see the return of several, but not all, of its original parts.

Perhaps no other clock better proves the genius of the early pioneers of time keeping than the Orloj. Marking the minutes and hours is only one of the many measurements it provides.

The 607-year-old astronomical clock tracks Old Bohemian time, when the new day begins with sunset; Babylon time, which tracks the day from sunrise to sunset; Central European time, which is marked with a hand in the shape of the sun; and Star time, measured by the way the stars appear to move because of the earth’s movement.

A calendar dial (刻度盘)notes the days of the week, month and year, and a zodiacal ring (黄道环)shows the path of the sun and the moon through the sky. But, it is the astrolabe (星盘)that is the heart of the clock’s mechanical (机械的) operation. It tracks the position of the sun, the moon and stars, and has been a necessary tool for astronomers.

Over the centuries, the clock has been damaged and repaired, but, always returned to fully working order. Its longevity has inspired a number of sayings. One is that when the clock stops running, the Czech land will be thrown into war and privation (贫困). Another holds that who ever tries to affect the machine will die or go crazy.

Skala, who has been a clock master for 25 years, said he was honored when asked to take care of the Orloj eight years ago. Asked whether he believed the sayings, Skala smiled. “I didn’t believe the stories,” he said, “or else I would never be able to work on the clock.”

5 . The Great Barrier Reef's outlook remains “very poor” despite coral (珊瑚) recovery over the past year, Australian government scientists said Monday, just days before a UNESCO ruling on the site's world heritage (遗产) status.

The United Nations cultural agency recommended last month that the world's largest reef (珊瑚礁) system be placed on its endangered list because of damage to the corals largely caused by climate change.

The Australian Institute of Marine Science (AIMS) said the corals were now in a “recovery window” after a decade of harmful heat stress and cyclones (旋风). But such opportunities were becoming rarer due to the influence of climate change, the government agency, which has monitored the reef for 35 years, said in its annual report released today. “The increasing emergence of climate-related extreme weather events and starfish outbreaks is causing more severe and frequent pressures, giving the reef fewer opportunities like this to recover,”CEO Paul Hardisty said. The scientists surveyed 127 reef sites in 2021 and found hard coral cover had increased at 69 of the 81 locations surveyed in the past two years.

Separate scientific research released last October found the 2, 300-kilometre (1, 400 miles) system had lost half its corals since 1995, with a series of ocean heatwaves causing mass coral death.

Britta Schaffelke, research program director at AIMS, said the latest findings provided a slight hope that the reef still has the power of recovering. But she added that its future is still very poor because of the dangers of climate change and other factors that are affecting the reef.

UNESCO has urged Australia to take urgent climate action but the government has long resisted calls to commit to net zero emissions (排放) by 2050. The government has said it hopes to meet the target “as soon as possible” without harming its economy, insisting dealing with climate change requires a global effort. The reef was worth about US $4. 8 billion a year in tourism for the Australian economy and there are fears that an “in danger” listing could weaken its tourist appeal.

6 . Scientists from the University of Texas at Austin have finally solved the mystery of a huge fossil(化石）that has been unlabeled and unidentified sitting at a Chilean museum for almost a decade. The relic which looks like a flat football, is the largest known soft-shelled egg from a marine reptile（海生爬行动物）that lived on the earth over 66 million years ago. Measuring more than 11 by 7 inches» it is also the second-largest egg belonging to any known animal, only behind the now-extinct elephant bird.

The rare fossil named " The Thing" was discovered inside a rock formation in Seymour Island off the coast of Antarctica in 2011 by a team of researchers including David Rubilar-Rogers. Over the years, the paleontologist（古生物学者）at Chile's National Museum of Natural History has showed the strange fossil to every geologist that came to the museum. However, no one was able to identify “The Thing's" origin until Julia Clarke» a professor at UT-Austin's Jackson School of Geosciences, visited in 2018.

“I showed it to her, and, after a few minutes, Julia told me it could be an egg!" Rubilar-Rogers said.

To confirm Clarke's suspect, Lucas Legendre, a student at UT-Austin who led the study, examined the fossil under a microscope. Sure enough, he found several layers of membrane（薄膜），confirming that the fossil was indeed a soft-shelled egg, similar to the obvious, quick-hatching eggs laid by some modern-day snakes. “The shell is very thin,” said Clarke.

The fossil's identification led to an even bigger mystery—what animal could have laid an egg this size? After considering several potential parents, the researchers concluded that the egg was laid by an ancient marine reptile like a masseur（沧龙）. The fact that the rock formation where the egg had been found had fossil evidence of baby masseurs and the offspring of other marine animals further strengthened their theory.

7 . One billion people in the world are short of water. How can this problem be solved. Some suggestions have been to desalinate ocean water or to build enormous water pipelines from areas where water is abundant. (Suggestions such as these prove extremely expensive when they are actually used.) One possibility that scientists are considering is pulling icebergs from either the North Pole or the South Pole to parts of the world with a water shortage. Although many questions must be answered before such a project could be tried, moving icebergs seems a reasonable possibility in the future.

Engineers, mathematicians, and glaciologists from a dozen countries have been considering the iceberg as a future source of water. Saudi Arabia is particularly interested in this project because it has a great water shortage. Scientists estimate that it would take 128 days to transport a large iceberg (about 1/2 square mile) to Saudi Arabia. Yet the iceberg would be completely melted by the 104th day. Therefore, insulation would be essential, but how to insulate the iceberg remains an unsolved problem.

The problems in transporting an iceberg are numerous. The first problem is choosing the iceberg to pull. The icebergs that form in the North Pole are quite difficult to handle because of their shape. Only a small portion extends above the water — most of the iceberg is below the surface, which would make it difficult to pull. South Pole icebergs, on the other hand, are flat and float like table tops. Thus they would be much easier to move.

How can a 200-million-ton iceberg be moved. No ship is strong enough to pull such enormous weight through the water. Perhaps several ships could be used. Attaching ropes to an iceberg this size is also an enormous problem. Engineers think that large nails or long metal rods could be driven into the ice. What would happen if the iceberg splits into several pieces during the pulling. Even if an iceberg with very few cracks were chosen, how could it be pulled through stormy waters. Furthermore, once the iceberg reached its destination, very few ports would be deep enough to store it.

All of these problems must be solved before icebergs can become a reasonable source of water. Yet scientists estimate that it will be possible to transport them in the near future. Each year, enough icebergs form to supply the whole world with fresh water for a full year. In addition, icebergs are free and nonpolluting. As a solution to the world’s water problems, icebergs may be a workable possibility.

9 . Venice is suffering the worst flooding the city has experienced in 50 years. The city is “on its knees” and Venetian Mayor Luigi Brugnaro tweeted as water submerged (淹没) much of the famous historical city.

While floods are a normal part of life in Venice, they have never happened with such frequency before. Experts say that climate change is likely to blame.     1     The Venetian council voted against a measure to fight climate change just a few moments before their chamber (会议厅) flooded.

Flooding is just one of the many impacts from climate change that is being experienced with more frequency and globally threatens many vulnerable (脆弱的) areas and regions. There is a threat that is not often considered.     2     Natural and man-made heritage sites throughout the world are in danger of being damaged or destroyed by climate change.

    3     Some will be hit by flooding, like Venice, others by extreme weather events or rising temperatures. For instance, George Town, the capital of the Malaysian state Penang faces rising sea levels, landslides and more severe typhoons, while Yellowstone ecosystem in the western United States faces melting snows, more frequent wildfires and a changing ecosystem.

Changes in the ocean will have a profound impact on many of these sites.     4     And rising sea levels threaten to wash away many of the world’s great archaeological sites.

Experts say that the solutions to saving these sites will be varied, but many will be very expensive.     5