“Keep out or I'll chase you out! This is my property!” You hear this every spring. It is a long musical sound —a bird song! Birds use their songs to communicate different messages to one another. People who study bird sounds are learning their meanings.

    Usually it is the male that sings. Early in spring he sings to say that he has picked out a piece of property. He sings to attract a female of his same kind. Together they will raise a family in his territory (领地). He sings to tell all other birds of his kind to keep out.

    Each kind of bird has its own type of song. Cardinals sing something that sounds a little like “What cheer, cheer, cheer.” Towhees sing, “Drink your tea.”

    Most of the time, birds pay attention only to the songs of birds of their own kind. Cardinals answer cardinals, and song sparrows answer song sparrows. A cardinal knows that a song sparrow will not try to steal its mate. So you can see one reason why a cardinal may chase away another cardinal but will not bother a song sparrow.

    Most different kinds of birds eat different things. To find enough to eat, a bird needs a big piece of land to search in. Many kinds of birds have some ways of dividing up the land into territories. Song sparrows, cardinals ovenbirds, and white-throated sparrows are some of the birds that have territorial systems.

    Especially in early spring, birds work out the boundaries between their territories by singing “keep out” threats and by chasing and fighting each other. The birds continue singing to tell females that they have set up territories. Neighboring birds seem to agree that there are make believe fences between their pieces of property. Then they do not have to waste energy chasing each other instead of taking care of their young.

    Scientists guessed that some birds could recognize their neighbors by small differences in their songs. Two scientists who studied white-throated sparrows found that these birds can even tell the difference between songs of individual birds of their own kind. White-throated sparrows have songs that seem to say “I'm your neighbor” or “I'm a stranger” or “I'm your neighbor to the west.” Other kinds of birds could tell neighbors from strangers by their songs, too.

    If you choose a hot tourist spot for your holiday, you are likely to be drowned by a great number of tourists, noise and long lines. At this point you might wonder why you ever left home. Here are some tips to deal with crowds and avoid the trouble that might ruin your trip.

Book Tickets In Advance 

    Buy tickets online before you leave home, and skip the crowds and endless lines at your destination(目的地). Smart travelers can avoid the queue when visiting abroad with online ticket sales.

Talk To People

    You can ask the travel agency and the hotel for help. Ask questions, get maps, ask about taxis, restaurants and the sites you wish to visit. These people are experts and can save you lots of time trying to find things out for yourself.

Sign Up For Special Tours

    If there are any special events or tours being offered for your vacation, buy them in advance. Firstly they are usually cheaper bought in advance and secondly it makes sure you get booked in before they are sold out.

Visit During the Weekdays

    We all know that most sites and events are less crowded during the week than on weekends when people are off work and the kids are out of school. Flights are also usually cheaper on weekdays than they are on weekends.

Watch The Weather

    Mother nature controls a lot of what we do especially for outdoor activities. Check the weather forecasts and plan your indoor and outdoor activities according to the weather ahead of time.

    It is quite reasonable to blame traffic jams, the cost of gas and the great speed of modern life, but manners on the road are becoming horrible. Everybody knows that the nicest man would become fierce tigers behind the wheel. It is all right to have a tiger in a cage, but to have one in the driver's seat is another matter.

    Road politeness is not only good manners, but good sense. It takes the most cool-hearted drivers great patience to give up the desire to beat back when forced to face rude driving. On the other hand, a little politeness goes a long way towards reducing the possibility of quarrelling and fighting. A friendly nod or a wave, or thanks in answer to an act of politeness helps to create an atmosphere of good will and becomes so necessary in modern traffic conditions. But such behaviors of politeness are by no means enough. Many drivers nowadays don't even seem able to recognize politeness when they see it.

    However, misplaced politeness can also be dangerous. Typical example is the driver who waves to a child crossing the street at a wrong place into the path of oncoming cars that may not be able to stop in time. The same goes for encouraging old ladies to cross the road wherever and whenever they want to.

    An experienced driver, whose manners are faultless, told me it would help if drivers learnt to correctly join in traffic stream without causing total jams that give rise to unpleasant feelings. Unfortunately, modern drivers can't even learn to drive, let alone master the roadmanship(驾车技能). Years ago, experts warned us that the fast increase of the car ownership would demand more give-and-take from all road users. It is high time that all of us took this message to heart.

    Several Jobs That Will Be Automated By Artificial Intelligence(AI) And Robots

    Translator

    Image recognition software and voice recognition software are bringing some major advances to language translation．Applications like Google's Word Lens can translate words from signs and documents in real time and there ale a lot of translation apps that allow you to type in a word or phrase and will translate it for you．

    Some will even speak the phrase for you and raw word-to-word translation will be fully automated soon．

Fast food workers

    Automated ordering booths have already made their way into a few McDonald's restaurants around the world，and cooking positions could be removed next．The booths probably can't handle customer service problems well，so televideo systems could bring in an office employee to deal with complaints．

Field technician

    New advances in the Internet of Things could make this work obsolete ．

Low-cost sensors combined with high availability cellular／satellite communications and cloud technology are being started to automate and alarm these sites，and can be checked and maintained from a desktop or mobile device．

Sales representative

    But，e-commerce is changing how we make purchasing decisions，especially those where there isn't much differentiation among the major competitors．

    If you're selling a high-differentiation product and／or a high-price，low-volume product you have some job security，but if you're selling a high-volume，low-differentiation product，you better start polishing your resume，said Doug Camplejohn，CEO of Fliptop．“These kind of product sales are all moving online．”

    Wilbur and Orville Wright were the two youngest sons of Bishop Milton Wright, Wilbur was born on a farm near Millville and Orville was born in August in the house the family would come to occupy for more than 40 years in Dayton.

    Orville would discover in later years that he and Wilbur's first interests in flight began when they were children, with powered rubber-band-helicopter toys that their father would bring home for them from trips around the country. Orville and Wilbur would build duplicates（复制品）of these toys and bounce them off the ceiling. They were just crazy about these things for the reasons that they did not yet understand.

    Both boys loved to solve problems that seemed difficult to others. The more difficult the problem was, the more they saw it as a challenge. Exploring the unknown was such a joy for then that Orville once said, "I can remember when Wilbur and I could hardly wait for the morning to come to get at something that interested us. That's happiness."

    Putting their gift to work, the boys entered the printing business soon after high school. Orville designed and then built a printing press（印刷机）for this enterprise. At first, they did contract printing for other people, and soon one of their customers during the early 1890s was Father Milton's church. They also tried the newspaper business, and although their two newspapers, the West Side News and The Evening Item were considered to be of high quality, Dayton already had daily newspapers, so the Wrights soon returned to contract printing.

    Branching out into other areas, they also opened a bicycle business. Bicycling was the fastest growing sport in the country at that time, and their repair shop soon led them into building bicycles of their own design, often with tools of their own construction, such as the lathe（车床）driven by a one-cylinder gasoline engine built by Orville. The bicycle shop would provide the livelihood（生计）that would allow them to carry out their experiments on airplanes.

Once a blind man fell flat on his face, which was awful but finally harmless. His service dog, however, was trained lo tum to an adult if the owner had an epileptic seizure (癫瘤发作). While the dog did what it was taught, the first person it found was merely annoyed but not alarmed. Thankfully, the dog's owner was not in the situation of medical emergency. But the experience inspired him to share this information on social media, "If a service dog without a person approaches you, it means the person is down and in need of help," the owner explained. "Don't get scared, don't get annoyed, and follow the dog! If the first person doesn't cooperate, it moves on.

Referring to the accident, a TV presenter asked a dog trainer, Olivia, some basic questions about service dogs, including how humans should react if an unaccompanied service dog approaches them.

"What they're going to do is sniff and gently push your leg," the trainer explained, specifically noting that service dogs are not usually trained to jump or bark. "If you see a dog in a vest without a person around it, follow it." When asked if one should say something to indicate they're prepared to follow the dog, Olivia said," there's no clear command. Just start walking wherever the dog leads."

Olivia concluded the TV show by adding that those who rely on service dogs could train their companions to move along to someone else, if the first person the dog came upon reacted negatively to its request. Doing so could finally save the owner's life.