Most birds produce short, simple calls, but songbirds also have the ability of many complex vocal (发声的) patterns that help them attract mates, defend territory (领地), and strengthen their social bonds. Each songbird species has its own unique song patterns, some with characteristic regional dialects. Experienced listeners can even distinguish individual birds by their unique songs.

    A lot of what scientists know about bird song comes from studying zebra finches. A baby male zebra finch typically learns to sing from its father or other males, starting while it's still a baby bird in the nest. First comes the sensory learning stage, when the baby finch hears the songs sung around it and commits them to memory. The bird starts to vocalize during the motor learning stage, practicing until it can match the song it memorized. As the bird learns, hearing the tutor's song over and over again is helpful — up to a point. If it hears the song too many times, the imitation (模仿) becomes worse -- and the source matters. If the song is played through a loudspeaker, he can't pick it up as easily. But hide the same loudspeaker inside a toy painted to look like a zebra finch, and his learning improves.

    What if the baby never hears another zebra finch's song? Interestingly enough, it'll sing anyway. Isolated finches still produce what are called innate songs or isolate songs. A specific tune might be taught, but the instinct to sing seems to exist in a songbird's brain. Innate songs sound different from the “cultured” songs learned from other finches - at first. If isolate zebra finches start a new colony, the young birds pick up the isolate song from their fathers. But the song changes from generation to generation. And after a few generations, the melody actually starts to resemble the cultured songs sung by zebra finches in the wild.

    Enrique Iglesias is a most successful singer! Born in 1975 in Madrid, Spain, Enrique is the child of the famous singer Julio Iglesias. Enrique's mother is a journalist. His parents divorced in 1978. Although Enrique lived with his mother, she sent him to live with his father because of concerns about her son's safety. Enrique wanted to be a singer secretly, he didn't wish his father to know that and didn't want to live under his shelter. He sought his dream on his own.

    Enrique released(发行) his first album “Enrique Iglesias” in 1995. This album had a collection of rock ballads(民谣) and five singles from it went straight to the top spots in Latin music. This album was followed by another “Vivir” in 1997. Three singles from this album occupied the top spots on the Latin charts yet again! Enrique also found himself nominated(提名) for the “Favorite Latin Artist” at the American Music Awards. By 1998, he had released his 3^rd album, “Cosas Del Amor”.This year Enrique won the “Favorite Latin Artist”. “Bailamos” got him great fame. One of the songs in this album was also used in a movie. With the success of “Bailamos”, Enrique now already had many loyal fans. The album, “Enrique”, was released in 1999.

    The year 2001 brought more success for him. His album, “Escape” had a few singles that reached the top spots. Enrique became a household name. This album is his biggest successful album so far. “Hero” and “Don't Turn Off the Lights” soon turned Enrique into a super star. His next release in 2002 was a Spanish album “Quizas”. This album brought Enrique a “Latin Grammy Award” for the Best Pop Vocal Album. In 2007, he released another album “Insomniac” and the song “Do You Know” became an instantly popular song.

    His Excellency

    Kim Jong Un

    Chairman of the State Affairs Commission of the Democratic People's Republic of Korea

Dear Mr. Chairman,

    We greatly appreciate your time, patience, and effort with respect to our recent negotiations and discussions relative to a summit (峰会) long sought by both parties, which was scheduled to take place on June 12 in Singapore.

    We were informed that the meeting was requested by North Korea, but that to us is totally irrelevant (不重要的). I was very much looking forward to being there with you.

    Sadly, based on the unacceptable and unfriendly statement, I feel it is not proper, at this time, to have this long-planned meeting.

    Therefore, please let this letter to serve to represent that the Singapore summit, for the good of both parties, but to the detriment of the world, will not take place.

    You talk about your nuclear capabilities (能力), but ours are so massive and powerful that I pray to God they will never have to be used.

    I felt a wonderful dialogue was building up between you and me, and ultimately, it is only that dialogue that matters. Some day, I look very much forward to meeting you.

    In the meantime, I want to thank you for the release of the hostages (人质) who are now home with their families. That was a beautiful gesture and was very much appreciated.

    If you change your mind having to do with this most important summit, please do not hesitate to call me or write. The world, and North Korea in particular, has lost a great opportunity for lasting peace and great prosperity and wealth. This missed opportunity is a truly sad moment in history.

Sincerely yours,

Donald J. Trump

    President of the United States of America

    Demand for the Chinese tech company's devices(设备) is red hot even though the country's overall market for smartphones is getting smaller Huawei's China sales rocketed more than 20% in the final quarter of 2018, and experts say that's partly due to the US government's global campaign against the company.

    “The latest tension between the US and China raised the patriotism(爱国主义) in Chinese consumers, said Jusy Hong, an analyst at research firm IHS Markit.

    He pointed out that some Chinese companies encouraged employees to buy Huawei phones late last year. The moves were a gesture of support after the firm's chief financial officer was arrested in Canada in early December at the request of the United States.

    Huawei's booming sales show how major parts of its business continue to increase even as the United States tries to persuade other countries to shut Huawei products out of 5G wireless networks and pursues(追究) criminal charges against it. The company expects to overtake Samsung as the world's biggest smartphone maker by next year.

    Huawei sold 30 million phones in China in the last three months of 2018, nearly three times as many as Apple(AAPL), according to data published this week by research firms Canalys and IDC. Apple's sales plunged almost 20%.

    Huawei's success in China, the world's largest smartphone market, is more than about geopolitics(地缘政治). Chinese consumers love its flagship, high -end- phones because they have great cameras, cutting edge technology and cost less than the latest iPhones, according to analysts. And by offering a selection of cheaper phones, Huawei is able to target a bigger market.

    It also benefited from the troubles this year at ZTE (ZTCOF), a rival Chinese smartphone and telecommunications equipment maker. ZTE was banned by the US government from buying vital American parts for months last year.

    If you think American cooking means opening a package and throwing the contents into the microwave oven (微波炉), think again. On the one hand, it's true that many Americans have cold cereal for breakfast, sandwiches for lunch and instant (方便的) dinners. From busy homemakers to working people, many Americans enjoy the convenience of fast food that can be ready to serve in 10 minutes or less. On the other hand, many Americans realize the importance of cooking skills. Parents—especially mothers'—see the importance of training their children—especially daughter's. Most Americans think that there's nothing better than a good home-cooked meal. But with cooking, as with any other skill, good results don't happen by accident.

    Probably every cook has his or her own way of cooking. But there are some basic skills that most people follow. For example, baking is a main method of preparing food in America. For that reason, Americans would find it next to impossible to live without an oven. American cooks pay special attention to the balance of foods, too. In planning a big meal, they try to include meat, a few vegetables, some bread and often a dessert. They also like to make sure the meal is colorful. Having several different colors of food on the plate usually makes for a healthy meal.

    For those who need guidance in their cooking, or for those who have just run out of ideas, recipes are a great help. Recipes list all the ingredients for a dish (generally in the order used), the amount of each to use, and a description of how to put them together.

Even though it is just a few years old, the comic strip, Cul de Sac, has already won many fans through its characters. So when cartoonist, Richard Thompson, announced that he had been diagnosed with Parkinson's disease, his fans sat up and took notice.

One of the fans was Chris Sparks, a designer and web developer in North Carolina. Sparks was building a website for Thompson when the cartoonist announced his disease. He started reading more about Parkinson's disease through books and websites. There he found that people could form public fund-raising teams to raise money for Parkinson's research. He quickly decided to form his own team: Team Cul de Sac.

However, Sparks decided to take a different path. He has contacted dozens of cartoonists around the world, who will contribute artworks inspired by the Cul de Sac strip. Thompson's publisher, Andrews Mcmeel, has agreed to release them in a book next year. Some of the profits from the book will go to the research. And after the book is released, the artworks will be auctioned off. All profits will go to the research team. The aim is to raise $450,000 for the foundation. "We've already had around 80 people who say they are interested in contributing", says Sparks.

Although many people with Parkinson's disease are private about their condition, Thompson is not one of them. He's happy to put his support behind the project. "I think we can make a difference," says Sparks, who points out that his love of comics inspired him. "I've been reading comics since I was 5 years old, and most of the cartoonists I've met have been wonderful human beings,"he says. "They've made a difference in my life, and I hope to make a difference as well."