Most nations have at least one type of food that people from other countries think is unusual or unacceptable to eat. In France, people eat horse meat and frog legs. In South Korea and parts of China, restaurants serve dog meat. And in Australia, it's common to cook kangaroo meat on the barbecue and use emu eggs to make pancakes.

    The kangaroo and emu are native to Australia. Both animals are important to the national image of Australia and appear on the Australian coat of arms. They're also central figures in the history of the native Australians. However, they still hunt these animals for their meat, fur and fat.

    Today, Australian people continue to eat these animals. One of the reasons people eat kangaroo meat is that it's high in protein and low in fat, so eating kangaroo is a good option for anyone on a diet. It's also cheaper to eat kangaroo meat than other red meats. Because of this, a lot of university students choose to buy kangaroo meat. BBC News also reported that Australian scientists believe that eating kangaroo meat is good for the environment— kangaroos have different digestive systems than cows and sheep, meaning they produce less methane, the second biggest contributor to global warming.

    While emu meat is high in iron and vitamin C, most people don't think it tastes good. For this reason, they prefer emu eggs. One egg is large enough to make seven omelettes (煎蛋). And while ifs illegal to collect emu eggs from the wild, they can be bought from emu farms. Rather than cracking the beautiful dark shell, it's better to dry it by putting a small hole at each end and blowing. Afterwards, you can even carve a design into the eggshell.

    It was dawn of March 21, 2018. Gary Messina was on his morning run along New York City's East River. Suddenly something caught his eye – a large 60-year-old man balancing on the four-foot-high fence that guarded the path from the water. As Messina got closer to the scene, the man took a step forward and slipped into the dark river below.

    When Messina reached nearer, the man was struggling in the water, clearly unable to swim. Other joggers also heard the man's cry. David Blauzvern and John Green dropped their phones and keys on land and jumped in. “People had called the police, but it was unclear when they'd get there.” says Green. “We just reacted.” Messina joined them in the river. Just as the jumper was losing strength, Blauzvern take hold of him. The pair were about 30 yards from the seawall when Messina and Green caught up to them. They seized the man, with Blauzvern supporting his back and Messina and Green holding him up from either side. As the men made their toward the concrete seawall that stretched (延伸) for blocks in each direction, Blauzvern had an awful realization: there was no way out of the river.

    By now, a crowd had gathered on land. “A rescue boat is on its way,” someone yelled to them. Swimming forward was getting tougher by the minute. The jumper, who was six foot two and weighed around 260 pounds, was heavy in his rescuers' arms. After ten minutes, they managed to get to the river's edge. “I've never been so out of breath,” says Blauzvern.

    Fifteen minutes after the men had jumped into the river, the two-man rescue boat appeared. But because it couldn't risk getting too close to the seawall, the men had to swim out to it. “I was completely out of energy at this point,” says Blauzvern. The men in the water pushed the jumper while the men in the boat pulled him up and, finally, to safety. The man they had saved was taken to the hospital for evaluation(评估). Details on his condition have not been known. As for the rescuers, each of them was at work by 10:30 a.m. “I was a bit late,” admits Blauzvern, smiling. “But I had a good excuse.”

    One day a few years ago, a very funny thing happened to a neighbour of mine. He is a teacher at one of London's big medical schools. He had finished his teaching for the summer term and was at the airport on his way to Russia to give a lecture.

    He had put a few clothes and his lecture notes in his shoulder bag , and he had put Rupert , the skeleton (人体骨架）to be used in his lecture , in a large brown suitcase. At the airport desk, he suddenly thought that he had forgotten to buy a newspaper. He left his suitcase near the desk and went over to the shop.

    When he got back he discovered that someone had taken his suitcase by mistake. He often wonders what they said when they got home and found Rupert.

    Dr. John Wilkins was a natural philosopher who lived from 1614 until 1672. He was crazy about getting to the moon and meeting the people who surely lived there. Wilkins believed that anything as Earth-like as the moon must have been created by God for living beings, and he was determined to meet them — despite the fact that he was three centuries ahead of his time.

    In the 1600s, the scientific understanding of gravity and outer space was limited. Wilkins believed, like many 17th-century scientists, that there was no difference between the atmosphere of Earth and the conditions in space, and that Earth's pull was due to magnetism (磁力). It was only reasonable, then, that Wilkins believed a two-wheeled horse-drawn battle car with wings with enough speed could lift high enough off the ground to break free of Earth's magnetic pull and reach the moon.

    Then Wilkins moved on to more pressing issues with his remarkable ability to think of new ideas: How would travelers feed themselves during the journey? He theorized that the main cause of hunger was simply the act of working against gravity, so getting to the moon without being burdened by it would be able to be realized. There was some knowledge at that time about the fact that air gets thinner and colder the higher up you go, but he had a fix for that too, "moistened sponges (湿润的海绵) might help us against its thinness".

    By studying the way in which birds fly, which also happened to be part of the studies that led to planes and rockets centuries later, Wilkins put his theory to the test with the help of a colleague, Robert Hooke. Neither of the two ever recorded their attempts, but it's somewhat safe to say that it didn't work out. Hooke himself may have been the reason he gave up hope, in fact, since he was part of the team that discovered space was a place without oxygen.

    Nowadays six Amazon Scout delivery robots rolled out in a pilot program in Snohomish County, Wash. The robots carry meals, groceries and packages to homes and offices in this region just north of Seattle. They have appeared on the sidewalks of London, Beijing and other cities and communities worldwide. These machines must overcome pedestrian legs, naughty dogs and broken pavement, which raises some questions.

    These services are gaining attraction as a growing number of city residents expect immediate or scheduled delivery for just about everything. Between 2017 and 2018 online retail sales in the U.S. increased by 16 percent. On the final step of all these deliveries, called the last mile, humans on bicycles, motorized scooters (电动车) or large delivery trucks typically deliver packages. All the vehicles compete for space on busy urban streets. "Deliveries are trending upwards in all crowded city centers, and if city and state leaders don't start thinking about creative solutions like robot deliveries, we can expect even worse traffic jams," says Paul Mackie, director of a transportation policy research center in Arlington.

    A study by this center found 73 percent of delivery vehicles in Arlington were parked outside of authorized areas, often blocking bike lanes and crosswalks. By moving the last step of deliveries from the road to the sidewalk, cities could reduce traffic jams and solve the parking problem entirely, Mackie says.

    Companies such as Amazon are not developing this delivery technology simply to clear up urban traffic. Self-driving vehicles and sidewalk robots could cut down last-mile delivery costs in cities by as much as 40 percent, according to a 2018 report by a consultancy firm. A delivery robot can cost thousands of dollars to manufacture, and most currently require human management and conservation. But in the long run companies that use autonomous delivery vehicles in the next several years could end up saving billions of dollars, the report stated.