The United States has always been a country of many cultures. Before Europeans came to North America, many groups of Native Americans lived here. Different Native American groups had different cultures. The first Europeans in the United States were from England and Holland, but immigrants came from all European countries. Many people also immigrated from Asia and Africa. Sadly, many Africans were brought to the United States as slaves. Many immigrants come from Latin America too. Today, the United States has people from more cultures than ever.

    In the 19th century, people spoke of the United States as a “melting pot.” People thought that all immigrates should forget their native cultures and languages and become English-speaking Americans. They felt that people should assimilate-join American culture. However, not everyone wanted to assimilate completely. Many people tried to keep parts of their cultures, such as foods, customs, and languages. However, their children often forgot their parents' or grandparents' language. But most Americans, even those whose families have been here a long time, can tell the countries their relatives came from. And of course, new immigrants take great pride in their curare and language.

    For all of these reasons, melting pot is no longer a good way to describe the United States. Instead, people now call the United States a “salad bowl.” They say salad bowl because in a salad, you can still see all of the individual parts (lettuce, tomato, and so on), but all the different parts mixed together and begin to take on the flavor of one another.

    Some educators told us that more years of school could help students get higher scores on intelligence tests. That was a finding of a study of teenage males in some countries. Now, another research shows that physical activity may help students do better in their classes.

    The research comes as educators in some countries are reducing time for activities like physical education. They are using the time instead for academic（学术的）subjects like math and reading. The studies appeared between 2008 and 2014. They included more than 55, 000 children, aged 6 to 18.

    Amika Singh:“ According to the results of our study, we can conclude that being physically active is beneficial for academic performance. There are, first, Physiological explanations, like more blood flow, and so more oxygen to the brain. Being physically active means there are more hormones(荷尔蒙)produced like endorphins(内啡肽). And endorphins make your stress level lower and your mood improved, which means you also perform better.”

    Also, students taking part in organized sports learn rules and how to follow them. This could improve their classroom behavior and help them keep their mind on their work.

    The study leaves some questions unanswered, however. Ms. Stash says it is not possible to say whether the amount or kind of activity affected the level of academic improvement. This is because of differences among the studies.

    The researchers said they found only two high-quality studies. They needed more high-quality studies to confirm (证实) their findings. They also pointed out that “results for other parts of the world may be quite different.”

    Still，the general finding was that physically active kids are more likely to do better in school. Ms. Singh says schools should consider that finding before they cut physical education programs. Her paper on “Physical Activity and Performance at School” is published in the Archives of Pediatric and Adolescent Medicine.

    Emma and Ryan, a married couple, were driving to a friend's house when Emma turned to Ryan and asked, “Would you like to stop for lunch?”

    Ryan replied. “No, I'm not hungry yet,” and continued driving. Meanwhile, Emma sat quietly fuming (十分恼火)in the passenger seat. Ryan could not understand why Emma was unhappy. He had thought she was asking if he was hungry, but in reality, Emma was telling him that she was hungry and wanted to stop for lunch.

    Misunderstandings like this often occur between men and women, even among people from the same culture. Deborah Tannen, professor of linguistics at Georgetown University in the United States, has studied conversational rules.

    In Emma and Ryan's situation, Emma was making a request in the form of a question. Her style of talking is common for women. She needed Ryan to agree they were both hungry. So, Emma asked Ryan what he wanted. She was really telling Ryan what she wanted; however, Ryan did not understand this. If he had been hungry, he would have said something more direct, such as, “I'm hungry. Let's have lunch.”

    Tannen believes that most women grow up in a world where talk is used to express feelings. However, most men are raised differently and they tend to keep their feelings to themselves.

    Tannen says, for men, talk is often used as a situation used outside the home to gain respect, to entertain and get attention , or to exchange information. This is why men communicate by making each other laugh, or talking about sport and work. These men do not always feel it is necessary to talk to feel close or to express their feelings. Women, on the other hand, are encouraged to speak about their feelings since this is a way to build relationships.

    On a flight from Dallas, Texas, to Cincinnati, Ohio, to visit a friend in 2013, event planner Paige Chenault daydreamed about the grand birthday parties she'd throw for her daughter one day. (Paige was five months pregnant at the time.) Then, flipping through a magazine, she saw a photo of an impoverished Haitian boy, skinny. "I thought, this kid has nothing," Paige says.

    The image stayed with her, and she resolved to do something to help. "I decided I would use my talents to throw birthday parties for homeless kids," Paige says. For the next four years, Paige and her husband, Colin, took time out from parenthood to visit shelters to determine how best to pull off the parties.

    Finally, in January 2017, Paige launched the Birthday Party Project, a nonprofit organization, and recruited friends and family to help decorate Dallas's 75- occupant Family Gateway Shelter with balloons and streamers, celebrating the birthdays of 11 boys and girls, with 60 more homeless kids in attendance. "That first party was better than I could have ever imagined," says Paige.

    Now Paige and her staff of three paid employees work with regional volunteers to plan monthly themed parties at 15 shelters across the country, some of which house abused or abandoned kids. Each child celebrating a birthday that month gets a $30 gift, a decorative place mat, and an individual cake or cupcake.

    One of Paige's favorite parts of each party is when the kids make a wish and blow out the candles. "They rarely get a chance to dream big," says Paige.

    Her daughter, Lizzie, now seven, often helps out at the parties. Paige says, "The one thing I've always wanted is for my kid to be generous."

    What if we could replace oil with a fuel which produced no pollution and which everybody had equal access to? The good news is that we can, in fact, we are swimming in it -literally.

    Hydrogen is one of the building blocks of the universe. Our own sun is basically, a big，dense cloud of the stuff. And hydrogen can be used to create electricity for power, heat and light.

    The problem is that hydrogen is everywhere and nowhere at the same time. It does not exist as a material on its own, but is always part of something else. So it has to be separated before it can be used.

    Most commercial hydrogen in use now is created from natural gas. As oil will start to run out in around the year 2030. It makes sense to produce as much hydrogen as possi­ble as soon as we can. But natural gas supplies will also begin to run out soon after. Another source is needed.

    Researchers are now using electricity to make water into hydrogen. Companies are working on the problem in their own areas. The first commercial hydrogen "fuel cells" for computers and mobile phones have already come on to the market Auto companies have also invested over US $2 billion in the production of hydrogen fuelled cars.

    The nations of a hydrogen fuelled planet would not fight over energy recourses. There would be a great reduction in pollution, the only by-product of creating hydrogen is pure drinking water something that is very scarce in many parts of the world. But that is not where the good news ends, once the costs of producing hydrogen have been brought down, it will possibly provide power for a third of the Earth's popula­tion that has no electricity.

    And electricity creates wealth. In South Africa over the last decade there has been a large programmer of electrification. Thanks to the programmer, people do not have to spend their days looking firewood to burn for heat and with electric light, they can work long into the night

Some scientists see radical changes in the way the human race co-operates. Hydrogen creates electricity, and is also created by it. With dual use fuel cells, everyone who consumes energy could also produce it. Late at night, a man drives home in London and connects his car into the "worldwide hydrogen web", which it supplies with electricity. A few hours later, a man in Beijing uses that electricity to power the hydrogen cell in his car. Hydrogen could be the first democratic energy source.

    Like all dreams of the future, it seems very far away. But the threat of war and terrorism in the Middle East has made governments and businesses more aware of the need to end oil dependency and spend more time and money on hy­drogen resource. So maybe the threat of war is not a completely bad thing for the future of the human race.

At age 22, Hikari Oberman has already been a lifeguard for four years. Last week, Oberman talked to The Garden Island about how he helped save lives during a recent rescue.

On Dec. 30, Oberman and his coworker Cope were parked in their truck at Anini Beach when two workers ran up to them and said, "I think someone's getting stuck in the channel!"

"I grabbed our equipment. We started rolling out down there," Oberman said. When he got out there, Oberman found a standup paddler, a man in his late 30s, struggling against the current, with an elderly man holding tightly to the back of the paddleboard (冲浪板).

He said, "My coworker grabbed the standup guy. Meanwhile, I'm stuck with the older man. "

Normally, Oberman said he would pull the paddler up, lay him on the surfboard, climb up behind and paddle from there. He tried that technique at first and quickly realized it was not a practicable option. They are not going anywhere.

Waves hit against the extremely sharp reef very hard about 30 yards behind them, and the current was pulling them into it.

"It's right behind us. If I stop paddling, we're definitely going to be in that zone." He said.

They started making progress toward the reef, where they might safely be able to climb out. Oberman just focused on forward movement.

After about five minutes-"even though it felt longer" -Oberman said his partner had gotten the paddleboarder safely to shore and started coming back out to help.

"I look back, and I see our Jet Ski. He's finally coming in the channel. We're not going to have to worry about that now. "

It was a good rescue.

When asked what it feels like to save someone's life, Oberman responded, "I love it! That's why we do it!" But as exciting as it might be to perform a big rescue, he explained that the most important part of his job is to keep people from getting into trouble in the first place.