This past Christmas season, I went to visit my parents. During the visit, I found the letters written by my parents to each other during the war in the attic (阁楼). The letters were piled high, dirty and had not been touched for decades. I asked mother and father if I could take the letters back to my home. They agreed.

    As I opened each letter, all of them beautiful with age, I discovered a new page in this private part of my parents' lives. My father served in the army. His letters were full of frontline (前线) descriptions, and they continued all the way through the battle. Each of my mother's letters was sealed (密封) with her lipstick kiss. Father wrote that he sealed his return letters by rekissing her lipstick kiss. How they had been missing each other! I finished reading six months of the letters and discovered there were at least eleven months missing. Maybe they were lost forever.

    Not long after our Christmas visit, Father became very ill and was in hospital. I went to the hospital to see him. As I sat by his bedside, he told me how much receiving those lipstick-kissed letters had meant to him when he had been so far from home.

    Later that evening, Mother and I revisited the attic in search of the lost letters. Finally we dug them out of Mother's old college trunk (皮箱). The next day was Valentine's Day, and we went to the hospital. At my father's bedside, I showed him an old envelope. His curiosity was aroused. When he carefully opened the letter, he recognized it and his eyes were filled with tears. He read the love messages that had been delivered years before to my mother in a quavery (颤抖的) voice. This Valentine's Day, we were lucky that we had everything.

    Americans think that everything we British people say sounds smart. We think that they sound low-class, but secretly we think they sound cool. These are just stereotypes about British and American English, but there is some truth in them.

    What is certainly true is that the differences between British and American English continue to interest us.

    When the US was only around 20 years old, people were already saying that British accents sounded more intelligent, according to Erin Moor's book. That's Not English: Britishisms, Americanisms, and What Our English Says About Us.

    However, there are many different accents in Britain—Moor says the UK may have just as many regional accents as the US, even though the population is around one-fifth the size. In the UK, accents are much more related to class, but to many Americans, even an accent that British people think is “low class” is thought of as intelligent and superior, according to MPR News.

    American slang has been part of British people's vocabulary for a long time—the amount of American television, movies and music enjoyed in the UK means that British people have been using words like “cool” and “awesome” for years now. But sometimes words from the UK make it to the US—like “gobsmacked”.

    “Gobsmacked” started as slang (俚语) from northern England. “Gob” means mouth, so the word means “surprised as if someone smacked (掌掴) you in the mouth”. Reality television brought it to the US, Moor said. When the singer Susan Boyle became famous for her unlikely great singing voice on the show Britain's Got Talent, she used it all the time. “I'm gobsmacked,” she repeated, and it got popular.

    “Americans love a colourful piece of slang as much as anyone else,” said Moor. And this is just one example of how Britons and Americans can leave each other “gobsmacked” with their different types of English!

    The National Postal Museum is divided into galleries that explore America's postal history. Visitors will have a full picture of the creation and fantastic varieties of postage stamps.

    World of Stamps

    Video images bring stamps to life and attract visitors who explore the surrounding displays. Visitors encounter the world's first postage stamp — the 1840 Penny Black and learn how it revolutionized communication. Stamp images, including Dr. Martin Luther King's "I have a dream" speech and the stamp that helped raise almost $72 million dollars for breast cancer research, explain how stamps have shaped history and honored people and places worldwide.

Gems of American Philately

    Visitors have the opportunity of examining 13 of the most rare and highly valued stamps in the world of the stamp collection, including the most famous American stamp of all, the 1918 Inverted Jenny. A video explains why the Inverted Jenny and other stamps displayed here are the most valuable. The treasures in this area are rarely available for public viewing. Each tells a story about an important event in US history.

    Mail Marks History

    The markings on mail provide valuable clues to the surprising ways mail has been transported over time, including challenges and even disasters encountered along the way. You will understand these markings by following the journeys of three historic letters.

    Connect with US Stamps

    Visitors explore their own connections with stamps. At three touch screen tables, they create their own stamp collection based on the topics that interest them most. They can also create their own stamp designs. Visitors have the chance to view videos in which stamp designers talk about their craft, stamp collectors explain what they collect and why, and footage(片段) shows the process of making stamps.

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.

    Some of Australian cyclists have used "GPS art" to turn a 202 km (125 mile) ride into the outline (轮廓) of a goat, which interests many people greatly.

    The four men marked their route on an app before using it track their journey around Perth. When uploaded to the computer, it was shown as a picture. Cyclist Ben Jones said the group settled on a goat because it was an easy animal to draw. He said the ride lasted more than six hours, with the four men stopping only for food, and flat tyres. "Except for riding 202km,' it's relatively simple," Mr. Jones told the BBC. "You mainly mark your route on the app and it plans directions out."

    GPS art has also been widely used by runners and other cyclists when they travel out. Mr. Jones said his group wanted to shake up their normal weekend ride. "We all ride 10, 000km to 15, 000km a year," he said. "Mostly we just ride together as mates and have a good time—that's what this was about."

    The group received much attention after posting their map to social media this week. Others described Mr. Jones as a goat guy in an interview on Australian television. For their next piece of GPS art, the group plans to draw a local animal such as the koala. "Certainly, there'll be something coming, for we are making our decisions to put more and more plans into practice. I'm sure of that," Mr. Jones said.

Western monarch butterflies(帝王蝶)spend their winters on the central California coast. A few months later, they produce young in the Central Valley and as far north and east as Idaho. But where they go in between remains an open question to biologists. Therefore, a group of biologists call on anyone who spots a monarch north of Santa Barbara this spring to get a quick shot(镜头)and email them the photo with a date and a location.

"Something's going on in early spring," said Cheryl Schultz, a professor at Washington State University Vancouver. "Winter survival isn't the problem in the short term, but they don't know whether the monarchs are not making it producing places, not finding plants to feed themselves along the way," she said.

The Western monarch population stood in the millions in the 1980s. In 2017, an annual count found 200,000 butterflies. In 2018, the number fell to about 30, 000-a figure that held steady last year. The monarchs' decline is part of a large trend among dozens of butterfly species in the West. What exactly caused the decline? Biologists attach it to a variety of reasons. Many chemicals are sprayed on the milkweed(乳草)monarchs will feed on. Climate change also plays a role in challenges facing monarchs. Yet, they're not nearly as threatening as those leading to loss of their living room. Farms used to have rough borders that were grounds for the plants monarchs love and live in. However, newly applied practices pushed crops to the edge of fields.

"Butterflies often have good and bad years. We do think there's potential to turn the situation around." Dr. Schultz said. And she said she saw two reasons for that. First, the population decline seen in 2017 ~ 2018 wasn't repeated last year. And second, she's seen butterfly populations recover before.