Moksh Jawa, 16, a student in the second year at Washington High School in the US, has already become a legend among students. “Why not?” might be his favorite question to ask.

His high school didn’t teach coding. As a sophomore in this school, he developed his own online course and helped his classmates get through it while a student in higher grades enen couldn’t do like him.

Everything he did came from his own interest. “I just fell in love with computer science,” Jawa said. Along the way, he lit a fire of curiosity and passion among classmates to learn coding too.

“All of my friends, especially the girls, were really, really afraid of computer science,” he said. But the subject and exam weren’t things to be feared, he said. “Computer science is all about logic (逻辑), not about how smart you are.”

To make his knowledge available online, Jawa set about creating his own online course, with easy-to-follow lessons.

The course has so far attracted 3,200 students across the US and in 120 countries and regions, including China, Ukraine and Algeria. It shows, Jawa said, the huge need for coding lessons.

When video lecturing, “I deliver it like I’m talking from one high school student to another,” Jawa said. “It’s always great to make it as clear and fun as possible, and to try to keep my voice as energetic as possible.”

He also does that, when teaching members of the computer science club he founded at his high school.

“His tutorials (辅导) were great,” said junior Taj Shaik, the club’s co-president, who took the whole course last year. “I’m definitely one of the early adopters of Moksh.”

“He’s pretty amazing,” said Bob Moran, principal of Washington High School, who saw him lead the club. “He was just a fantastic teacher – clear, organized and entertaining. When a student got the right answer, he would throw them a piece of candy.”

【推荐2】After paying ￡20 for my racing red ukulele(尤克里里琴) at a music shop, I turned up to the “Ukulele Hootenanny” at a club near Liverpool Street. The host came and tuned it for me. I went to get a drink and was about to start playing when the little man approached again and said, “Let me tune that again for you.” He took it and returned minutes later saying, “I’ve tuned it, but it won’t be worth it—use this one instead.” He handed me a racing red version of a more expensive ukulele that I happily fumbled(摸索) with on the night.

You can cover the basics online and come along expecting to be able to play the most commonly used chords(和弦). Just don’t expect to fluently flip(弹) between them without any mistakes—that is easier said than done.

What makes this hobby unique is the fact that the ukulele is not seen as a “serious” or “proper” instrument, and so it attracts those more likely to be picking it up for fun. That night’s crew were a random collection of around 30 people ranging from 20 to 60, with various shaped and sized ukuleles and various levels of ability.

We sat around a table, with two song books in front of us. The “leader” called out a page number as we flipped through to a well－known Johnny Cash or Queen tune and did our best to keep up. Later on we got to haggle(争论)—a Lady Gaga here, an Eric Clapton there.

But the part I enjoyed the most that I wasn’t expecting was the singalong. Everyone sings, and as no one cares about your singing abilities, people have a lot of fun with harmonizing, and putting on a heavy Southern accent even if it’s not a country song. What resulted was a hobby with a unique mix and thus one of my favourites: cheap, social, learning a skill, and above all great fun.

【推荐2】With the summer holiday around the corner, it seems that everybody is busy planning their vacations. Here are some tips that can help you enjoy your holiday without emptying your pocket:

Go to your destination while the demand is low and take advantage of huge discounts. During the peak season, the hotel and flight prices increase quickly.     1    .

Look for places that do not charge extra for children.     2    . If you and your family are going to stay for a longer period, renting a small apartment is a good choice.

    3    

Planning your meals is another way to reduce your travel costs. During your family trip, try new food the locals eat, which will save money.

Tourist-heavy places are known for overcharging for just about everything. Clothes, travel goodies, souvenirs, etc. are very expensive at these places.     4    . Bargain hard to get the best price.

    5    . Instead, take buses, railways or subways, which are always cheaper. If you are planning to stay for a while, you can consider renting a car.

【推荐3】Competition in the Olympics should be between athletes who use their own strength or speed. If some athletes don’t follow the rules, it ruins the fun for everyone connected with the game. It also gives an extremely unfair advantage to the athletes using drugs. So I think athletes should be tested for drugs.

—Jim from Atlanta

Drug use among top athletes has long been a problem. Without drug tests, the Olympics would be about who uses the most drugs, not who trains the hardest and has the most athletic skills. Also drugs do harm to people’s health and sometimes even kill people.

—David from Houston

Why should athletes be allowed to compete when it’s not really they who are actually competing? It’s the drugs that do all the work. Athletes who use drugs are like runners with roller skates. It’s cheating and irresponsible, which must be strictly forbidden. It’s unfair to other competitors who don’t use drugs.

—Bruce from Chicago

Most sports athletes are held to a standard of being drug-free. Olympians should not be held any differently. They take part in highly competitive sports and win medals for their country. Testing the athletes for drugs must be done in every country and every sport. No drug test would be unfair to athletes who don’t use drugs.

—Sam from Los Angeles

Although popular opinion is against athletes’ using drugs, I believe drugs do help make the Olympic sports more wonderful. I enjoy seeing human beings achieving things that couldn’t be done with normal conditioning. I enjoy seeing stronger, faster and longer performances by making good use of drugs. I don’t see the necessity of drug tests.

—Jack from New York

【推荐1】Teenagers are risk-takers. Those things may not be understood by the adults around them. Are they driven by poor judgment or immature (不成熟的)brains?

In their book Wildhood, the bestselling authors Barbara Natterson-Horowitz and Kathryn Bowers, present findings from their five-year study on wild animal adolescence(青春期). The two performed a complete survey of age-related   death in wild animals and found something   truly surprising—young folks are born to take risks, and with good reasons.

Life on Earth for adolescent and young adult animals is just as dangerous. In the wild young animals crash, drown and starve more often than their adult animals. And they are more likely to be targeted and killed by predators (捕食者).Old enough to be away from home? But new to the ways of the world? This time of life is risky for human adolescents as well. Wildlife biologists describe these unprepared creatures as predator naives(幼稚).

Facing death danger while still maturing is a fact of life for adolescents across species. Adolescents must have predator awareness if they are to survive. Said another way: To become safe, you must take risks.

Adult bats typically flee predators such as barn owls. But adolescent bats have been seen doing the opposite —flying toward them. This behavior can also be seen in other wild animals. Biologists call it “predator inspection(检查)”. Predator inspection provides young animals important information about their deadly predators. Familiarity with predatory strategies helps adolescents survive and even avoid future attacks. Predator inspection is one of the ways to help predator naives to become experienced predators.

Studying wild animal adolescence offers a new understanding of why teenagers act the way they do. Parents should balance the urge to protect with the need to let their teenagers test their wings. The research suggests that adolescents need some exposure to the dangers they will someday face on their own —and without knowing that, parents’ over protection maybe the riskiest behavior of all.

【推荐2】Instagram is about to take its biggest step toward removing likes from its platform. After months of testing an option to hide likes in select international markets, Instagram, which is owned by Facebook (FB), has already been testing hiding likes in seven other countries, including Canada, Ireland and Australia. For years, likes have been central to how celebrities, brands, politicians and everyday users experience Instagram and Facebook. It’s a way of measuring popularity and success. But in recent months, Instagram has been rethinking how likes contribute to making its platform more toxic. Now it’s considering a change.

The total number of likes on posts – which appear as hearts on the app – will disappear from Instagram’s main feed, profile pages and permalink pages. The owner of the account can still see their own likes, but their followers won’t know the count.

CNN Business previously spoke with users in countries with the test. The majority felt this move would improve well-being on the app. Instagram is the most detrimental social networking app for young people’s mental health, such as negatively impacting body image, according to one study.

But other users and psychologists said hiding likes won’t fix everything. The test doesn’t address some of the key ways that activity on Instagram can impact the well-being of users, including bullying, feeling left out and thinking other people’s lives are better than their own.

Renee Engeln, a psychology professor at Northwestern University, voiced his opinion that the biggest impact of Instagram is the content and the exposure to this constant stream of perfected images is what seems to hurt psychologically. Plus, users can still see their own likes – and feel badly if their posts don’t perform well.

【推荐3】Don’t like seeds in your tomatoes? You might be pleased to know that seedless ones have been created by gene editing.

This could create a wide range of seedless fruits, but few may ever be seen in the supermarket if regulators decide to treat gene-edited crops in the same way as genetically engineered ones.

Several seedless fruits, from bananas to grapes, are already available, but have mostly come about by luck rather than design. And although there are a few seedless varieties of tomatoes, they’ve taken researchers many years to create.

Now it can be done very quickly, as Keishi Osakabe at Tokushima University in Japan has shown. His team used the CRISPR gene editing technology to make fruits develop even though no seeds had begun to form. “We haven’t tasted them yet, but in theory they should taste the same,” says Osakabe.

There have been a few efforts to create seedless tomatoes using earlier genetic-engineering techniques. These methods take longer time compared with CRISPR.

Some “seedless” fruits just have very small seeds, and still require pollination (授粉). But completely seedless fruits like the edited tomato do not require pollination at all. Such plants could improve food security by reducing our reliance on smaller bee populations, says Saul Cunningham at the Australian National University. Many fruit growers buy bees to pollinate their crops.

There is a deficiency for farmers, however. Seedless plants usually have to be grown from cuttings, which involves more labor than planting seeds.

CRISPR could be used to develop other types of fruit that don’t require pollinator, as well as introduce beneficial mutations (突变), says Osakabe.

But to make it on to the supermarket, gene-edited plants may have to meet the same standards as genetically engineered plants, which would greatly increase costs. Some argue chat since gene editing is used to introduce mutations already found in some of the plants we eat, it should not require such strict regulations.