Have you ever wondered why birds sing? Maybe you thought that they were just happy. After all, you probably sing or whistle(吹口哨) when you are happy.

    Some scientists believe that birds do sing some of time just because they are happy. However, they sing most of the time for a very different reason. Their singing is actually a warning to other birds to stay out of their territory.

    Do you know what a “territory” is? A territory is an area that an animal, usually the male, claims as its own. Only he and his family are welcome there. No other families of the same species(物种) are welcome. Your yard and house are your territory where only your family and friends are welcome. If a stranger should enter your territory and threaten you, you might shout. Probably this would be enough to frighten him away.

    If so, you have actually frightened the stranger away without having to fight him. A bird does the same thing. But he expects an outsider almost any time, especially at nesting(筑巢) season. So he is screaming all the time, whether he can see an outsider or not. This screaming is what we call a bird's song, and it is usually enough to keep an outsider away.

    Birds sing loudest in the spring when they are trying to attract a mate（配偶）and warn others not to enter the territory of theirs.

    You can see that birds have a language all their own. Most of it has something to do with attracting mates and setting up territories.

Sea Life Melbourne Aquarium (水族馆)

    The all-new Sea Life Melbourne Aquarium, situated in the heart of Melbourne's CBD, is one of Victoria's leading visitor attractions and an unforgettable outing for the whole family. Having 12 amazing zones of discovery, Sea Life Melbourne Aquarium is the very place that you cannot miss when you visit the city.

    * Opening Times

    Sea Life Melbourne Aquarium is open from 9:30 am until 6:00 pm every day of the year, including public holidays. Last admission is at 5:00 pm, one hour before closing.

    * Location ( 位置)

    Sea Life Melbourne Aquarium is located on the corner of Flinders Street and King Street, Melbourne. It is siyuated on the Yarra River, opposite Crown Entertainment Complex.

    * Getting to Sea Life Melbourne Aquarium

    Train

    The Sea Life Melbourne Aquarium train stop is located on the free City Circle Tram route (公交线路) and also routes 70 and 75. City Circle trams run every 10 minutes in both directions.

    Shuttle Bus

    The Sea Life Melbourne Aquarium is a free bus service, stopping at key tourist attractions in and around the City. Running daily, every 15 minutes from 10:00 am to 4:00 pm.

    Car Parking

    While there is no public car parking at Sea Life Melbourne Aquarium, there are several public car parking lots available only a short walk away.

    * Wheelchair Access

    Sea Life Melbourne Aquarium provides people in wheelchairs with full access to all 12 zones. Each floor also has wheelchair accessible toilets.

    * Terms

    Tickets will be emailed to you immediately after purchase or you can download and print your ticket once payment has been accepted. Please print out all tickets purchased and present at the front entrance of Sea Life Melbourne Aquarium. No ticket, no entry!

    It was warm for a Sunday afternoon in early January. Kevin loved being outdoors among the wild rosebushes in front of his house with a view of distant mountains.

    It had been a good day for his wife, Sharon, too. They spent the morning in front of the house, talking and drinking tea. Sharon felt strong and tried her best to cook, starting a pot of homemade soup — a task that would have been nothing a few years ago, but is a little hard for her now. Her illness had left her weak, often puzzled.

    Sharon was the take-charge person in the family. She was seldom sick until 1997, when she began suffering from terrible headaches. One day at work, colleagues said she didn't look right and urged(敦促) her to go to the hospital. She rose from her chair and fell over. She could hear voices, but couldn't speak. It looked as if she'd had a stroke(中风).

    Other stroke-like symptoms (症状) followed. She had difficulty walking. She ran a fever all the time. The headaches never stopped. She and Kevin spent all their savings seeing doctors and on medical tests.

    In 2000, physicians said Sharon had brain damage that left her with symptoms resembling dementia (痴呆症). Once, she visited a familiar store and couldn't remember where the exit was. Another time, she was making spaghetti, but didn't know what to do after the water boiled.

    After seeing specialists, Kevin and Sharon came to believe that exposure(接触) to mould(霉菌) had caused Sharon's condition. Her world was certainly getting worse. At times she needed a wheelchair. The woman who never liked asking for help had to stay at home and rely on her husband.

    Born and raised in a digital age, today's young people are generally tech savvy (技术娴熟的). But when it comes to basic life skills, they're less capable than the older generation.

    According to a recent study, 69 percent of 18 to 24-year-olds in the UK have no idea how to bleed a radiator(暖气片换水). About 35 percent of them don't know how to sew on a button, while about 11 percent don't understand how to change a light bulb or iron clothes.

    It appears young people are losing the skills older generations took for granted. In fact, the problem is shared by young people in the United States. According to a report by Forbes in 2014, most millennial (千禧一代) drivers don't know how to check their tire pressure. Cooking is another basic life skill that has been dropped, as millennials are much more likely to order food deliveries than previous generations.

    Technology may be to blame for this generational gap. Skills at using phones and computers are the ones valued these days, and the practical skills are now seen as functions that can be easily outsourced (外包). Indeed, improvements in technology have made young people unfamiliar with many basic life skills. For example, with GPS always at hand, young people have had no need to learn how to read physical maps.

    However, this change has raised concerns among many people. “If you have your master's degree and you can't live within your means or go home from your job and feed yourself a nutritious (有营养的) meal, you're not a complete graduate,” Chris Moore, a professor from Brigham Young University, US, told Huff Post.

    That's why there's an increasing call for the return of “home ec” in the US, short for home economics, which teaches basic life skills like cooking and how to do laundry. It was very popular in the early 20th century, but was later taken out of schools and universities because of budget(预算) cuts. But recently, home ec was reintroduced in a small number of schools and universities.

    “The educational system would work better if every academic class had a practical course that applied the theory to do something regular people do in real life,” Robert Frost, instructor and flight controller at NASA, wrote on Quora, according to Huff post.

    Unlike most other holidays, the history of April Fools' Day, sometimes called All Fools' Day, is not totally clear. The only point in time that can be agreed on as the beginning of this tradition was 1582, in France. Before that year, the New Year was celebrated for eight days, beginning on March 25th. The celebration reached the highest point on April 1st. With the reform of the calendar under Charles IX，the Gregorian calendar(公历，阳历) was introduced, and New Year's Day was moved to January 1st.

    However, because in those days communications were not as developed as they are today, many people did not receive the news for several years. Some people refused to accept the new calendar and continued to celebrate the New Year on April 1st. These backward people were considered "fools" by other people. They  were often sent on "fools" errands(徒劳无益的工作)  or were made the targets of jokes.

    This developed, over time, into a tradition of playing a trick on someone on the first day of April. The tradition eventually spread to England and Scotland in the eighteenth century. It was later introduced to the American colonies of both the Britain and France. April Fools' Day thus developed into an international fun feast, so to speak, with different nationalities specializing in their own kind of humor at the expense of their friends and families.

A rainy day can be a chance to recharge. While you relax on the sofa with a movie, the raindrops falling on your windows might one day provide the power for your TV. This is the idea behind an invention that harvests energy from water. 

The technology is based on the triboelectric (摩擦电的) effect. An engineer at the University of Hawaii, David Ma knew that it was possible to generate electricity by rubbing two things together. So, he thought, "Why don't we use water?"

A drop of water sliding across a surface coated with two different materials would generate enough friction(摩擦) to create an electrical charge. By placing metal wires that the drop of water touched as it moved, it should be possible to harvest electricity, he reasoned. 

It worked. In fact, the researchers lit up 15 LED bulbs with a single moving water drop. 

This is not the first time that scientists have got electricity from water-generated friction. Earlier experiments, though, harvested the charge produced in a surface by a sliding drop of water. There, the surface had acted as an electrode(电极). This is different. The energy of friction is being harvested from the water itself. 

"The technology could someday power phones, sensors or other small electronics," says Christopher Oshman, an engineer at the Colorado School of Mines. "This work is a step towards harvesting the energy of moving objects all around us, including ourselves, to power the electronic devices we use every day," he says. 

"Ma has shown that the technology can work in a lab," Oshman says. Next, the Colorado researcher would like to see it tried on a larger scale, such as on an umbrella.