In recent years, remote-sensing technologies have become ordinary in archaeological fieldwork（实地考察）. Such tools for excavation produce rapid results and cause no damage to archaeological sites. They are highly accurate and usually cost effective. Here are three of the modern archaeologist's most trusted remote-sensing tools.

    As the simplest of the remote-sensing techniques that archaeologists use, aerial（空中的）photography allows experts to see aspects of a site that may be invisible from the ground, such as the way in which something such as a town, garden, or building is arranged and traces of old walls and roads. The technique involves taking photographs with conventional cameras and filming from airplanes, helicopters, hot-air balloons, or other airborne vehicles.

    Geographic Information System (GIS) contains a large amount of field data archaeologists typically collect in and around excavation sites. While in the field, archaeologists use GIS on their computers to make and manage detailed site maps, and they can combine the results of remote-sensing tests with maps of the region created with the aid of Global Positioning System. Resulting maps sort the most archeologically promising areas and display these sites three-dimensionally.

    Ranging in size from small handled models that one places against the ground to larger ones that one across a site, Ground Penetrating Radar (GPR) devices use low-power radio waves to detect changes underground. Unlike traditional radar, which broadcasts into the air and uses a dish to focus the returned waves, GPR uses a small but sensitive receiver placed directly against the ground. Depending on their needs, archaeologists can adjust radio frequencies upward for shallow sites or downward for deeper areas, though GPR devices produce the greatest definition（清晰度）when reading depths of three feet or less.

The Domestication （驯化）of Cats

    For centuries, the common view of how domestication had occurred was that prehistoric people, realizing how useful it would be to have animals kept for food, began catching wild animals and breeding （繁殖）them. Over time, by allowing only animals with "tame"（驯养）characteristics to produce their babies, human beings created animals that were less wild and more dependent upon people. Eventually this process led to the domestic farm animals and pets that we know today, having lost their ancient survival skills and natural abilities.

    Recent research suggests that this view of domestication is incomplete. Prehistoric human beings did catch and breed useful wild animals, but specialists in animal behavior now think that domestication was not simply something people did to animals—the animals played an active part in the process. Wolves and wild horses, for example, may have taken the first steps in their own domestication by hanging around human settlements, feeding on people's crops and getting used to human activity. The animals which were not too nervous or fearful to live near people produced their babies that also tolerated humans, making it easier for people to catch and breed them.

    In this version, people succeededin domesticating only animals that had already adapted easily to life around humans. Domestication required an animal that was willing to become domestic. The process was more like a dance with partners than a victory of humans over animals.

    At first glance, the laming of cats seems to fit nicely into this new story of domestication. A traditional theory says that after prehistoric people in Egypt invented agriculture and started farming, rats and mice gathered to feast on their stored grain. Wildcats, in tum, gathered at the same places to hunt and eat the rats and mice. Over time, cats got used to people and people got used to cats. Some studies of wildcats, however, seem to call this theory into question. Wildcats don't share hunting and feeding areas, and they don't live close to people. Experts do not know whether wildcats were partners in their own domestication. They do know that long after people had acquired domestic dogs, sheep and horses, they somehow acquired domestic cats. Gradually they produced animals with increasingly tame qualities.

    I began smoking at 13, with a friend in the evenings when we were out. I never thought of the damage it brought me. But I had a bad cough after a cold, and my teeth weren't as white as my sister's, who never smoked. I no longer played any sports. Since all my friends smoked, I never felt different.

    I met and married my husband Paul when we were 22，both smoking like chimneys (烟囱). I had two children by the time I was 26, and life went on as normal. We smoked around our children, never thinking it would be doing them any harm. They both begged us to stop when they learned about the hazards of smoking. We just rolled our eyes at each other.

    My parents quit smoking, and my aunts quit smoking, but they were older. I had lots of time to quit in my life. Paul's mother died of a heart attack at only 55, after suffering two diseases caused by smoking. And still we smoked.

    At the age of 36, I had a child with a breathing problem. We moved outside to smoke, as she had such trouble breathing, and we didn't want to add to that!

    Then my father died a few years later of cancer throughout his body. Still I smoked, even as he asked me on his deathbed to try to stop. I did mean to, but I thought that I had too many worries to deal with. How would I face them without a smoke? Little did I know then that the smoking was only adding to my inability (无能) to deal with trouble, clouding my whole world in smoke.

    Then Paul had an extremely serious problem in his heart because of a condition caused by smoking. Finally, I decided to quit smoking. I knew I'd suffer greatly too if I kept smoking. Paul decided to join me, of course. He had no choice if he didn't want to die.

    Luckily, we made it. Now I have enough energy, a joy in living, and more confidence than ever before.

    The famous director of a big and expensive movie planned to film a beautiful sunset over the ocean, so that the audiences could see his hero and heroine in front of it at the end of the film as they said goodbye to each other forever. He sent his camera crew out one evening to film the sunset for him.

    The next morning he said to the men, "Have you provided me with that sunset?"

    "No, sir," the men answered.

    The director was angry. "Why not?" he asked.

    "Well, sir," one of the men answered, "we're on the east coast here, and the sun sets in the west. We can get you a sunrise over the sea, if necessary, but not a sunset."

    "But I want a sunset!" the director shouted. "Go to the airport, take the next flight to the west coast, and get one."

    But then a young secretary had an idea. "Why don't you photograph a sunrise," she suggested, "and then play it backwards? Then it'll look like a sunset."

    "That's a very good idea!" the director said. Then he turned to the camera crew and said, "Tomorrow morning I want you to get me a beautiful sunrise over the sea."

    The camera crew went out early the next morning and filmed a bright sunrise over the beach in the middle of a beautiful bay. Then at nine o'clock they took it to the director. "Here it is, sir," they said, and gave it to him. He was very pleased.

    They all went into the studio. "All right," the director explained, "now our hero and heroine are going to say goodbye. Run the film backwards so that we can see the 'sunset' behind them."

    The "sunset" began, but after a quarter of a minute, the director suddenly put his face in his hands and shouted to the camera crew to stop.

    The birds in the film were flying backwards, and the waves on the sea were going away from the beach.

90 percent of the world's fireworks are produced in China. The biggest importer is the US, which {#blank#}1{#/blank#} (ship) in more than US $650 million worth in 2021.

The details of fireworks' invention are lost to history, but {#blank#}2{#/blank#} folk tale tries to fill in the gap. It goes that monk named Li Tian created fireworks around 1400 years ago by packing gunpowder into bamboo tubes {#blank#}3{#/blank#} (scare) off evil spirits.

An explosive mixture of gun-powder and chemical compounds (化合物) is {#blank#}4{#/blank#} makes fireworks flash in pretty colours and fun shapes. The images they make depend on the placement of these compounds inside the shell of the firework. Crowd {#blank#}5{#/blank#}(favorite) include "comet", featuring a long trail of sparks; "peony", a flower-like burst; and "strobe", which produces a blinking effect.

The single biggest firework shell ever shot was part of a 2020 winter-carnival display in Colorado, US. {#blank#}6{#/blank#} (weigh) 1268 kilograms, it rose more than a kilometre into the sky {#blank#}7{#/blank#} bursting, turning the night sky red.

For centuries we had to light firework {#blank#}8{#/blank#} hand, but since the 1980s, there's been another option: computer-controlled lighters, which made music at displays more {#blank#}9{#/blank#} (precise) timed and safer. An even greener alternative recently {#blank#}10{#/blank#} (adopt) is using drones to trace flashy patterns in the sky. The future of fireworks, like so much else, may be robotic.

Central Axis: The Backbone of Beijing

Beijing Central Axis (中轴线), running north-south through the heart of the old city of Beijing and governing the overall layout of the capital, is{#blank#}1{#/blank#}integration of building complexes and archeological sites. Initially constructed in the 13th century and shaped in the 16th century, Beilng Central Axis was continuously perfected over seven centuries, giving rise to a well-organized and imposing building ensemble that manifests (彰显) the {#blank#}2{#/blank#}(idea) order of the ancient Chinese capital deep {#blank#}3{#/blank#}(root) in the capital planning tradition for over two millennia.

From Yongding Gate to the Bell and Drum Towers via Zhengyang Gate, Tian'anmen, Taihe Palace, Jingshan Mountain, Beijing Central Axis connects the outer, inner and imperial city {#blank#}4{#/blank#} the imperial palace. The main buildings along the central axis are symmetrical and staggered in {#blank#}5{#/blank#}(high), thus creating a unique and magnificent picture. In addition to {#blank#}6{#/blank#}(form) the backbone of the frame of Beijing city, it serves as the best embodiment of the capital's boundless charm {#blank#}7{#/blank#}makes it a famous historical and cultural city.

The Central Axis of Beijing which links the ancient times and the present has experienced the changes of times and witnessed the continuous development of the Chinese civilization. Nowadays, the application for the world heritage status of Beijing Central Axis {#blank#}8{#/blank#}(include) in the core area planning already, and this amazing urban landscape is becoming a development axis that {#blank#}9{#/blank#}(highlight) the protection of the ancient capital and the development of the city. In the future, it will continue to glow (焕发) with vibrant charm and nourish the Chinese civilization which stands in the East of the world with a {#blank#}10{#/blank#}(calm) and more confident posture.