I returned home the other night, tired. My husband asked me how my evening was, “Great.” I told him. I had spent 90 minutes in a gym with 10 Ping-Pong tables and all kinds of players, all playing a little ball over the net. By 9 pm, I was excited, tired, satisfied. I had beaten two young men half my age and lost battles against other competitors. To an observer, the night was common. To me, it was a lucky thing that I hadn't expected.

    I had taken up Ping-Pong during college, and in my 30s took more advanced lessons. However, a serious accident hurt my leg, which made me unable to take exercise. Months later, I tried to play Ping-Pong but my leg pained for a week. I put the game out of my mind.

When I was 53, one day my bad leg was working a little bit better. Could Ping-Pong be possible for me, now—in my condition, at my age? I tried to play Ping-Pong again

    Ping-Pong is a sport which requires endurance(耐力). Players need quick foot work and upper body movements to return balls, requiring faster response time than tennis.

    Playing Ping-Pong offers benefits for the brain. A study of 164 women aged 60 and older showed that Ping-Pong improved cognitive(认知)function more than dancing, walking or gymnastics. “The great thing about our sport is that it can be played by anyone,” said Jimmy Butler, a four-time national USA Table Tennis Association winner. “I see 90-year-olds and 10-year-olds.”

    Years passed and my endurance improved. People started to praise my shots. I won a game. Then I won agin. These days, I feel wonderful, I believe this sport is the fountain (源泉)of youth.

    First Lady Michelle Obama is a big fan of volunteering. Volunteering means working for free to help someone else. Mrs. Obama says volunteering is very important. “It should be part of everyone's life,” she says.

    Many teens agree. They say that helping others feels great and makes a difference. These days, more teens volunteer than work for pay. Teens clean up parks, walk dogs at animal shelters, visit the elderly and more.

    Some cities —including Seattle, Chicago, and Washington, D.C. —require high school students to volunteer. Students must volunteer in order to graduate. The student volunteers learn new skills and help their communities.

    Many parents are in favor of the idea —they say volunteering helps teens build job skills. But most teens don't want to be forced to volunteer. They say they are busy. And they say volunteering is only fun if it's a choice.

Read both sides of the debate and decide.

YES

Volunteering can help teens get into college or get a job.

Many cities and towns need help. Volunteers can help keep important programs going.

Not all teens will volunteer if it isn' t required. Schools should require students to do all they can to get ready for adult life.

NO

Most teens are already very busy with classes, homework, jobs and sports. Forcing them to do more isn't fair.

It should be up to each person. Helping out doesn't feel as good if you have to do it.

Finding a volunteer job isn't always easy. Students shouldn't be kept from graduating because of something they can't control.

    Around this time a few years ago, it was common to see videos of friends on social media having a bucket of icy water thrown on them. Known as the “ice bucket challenge”, it was created as a way to raise money for the medical condition ALS. But now, there's a new challenge and this time, no water is involved.

    What is it? Well, think of a fruit that you'd never normally sink your teeth into. Perhaps you've got it: a lemon. While we enjoy using lemons to add flavor to dishes, very few of us would actually eat one as we'd eat an apple or an orange.

    But the horrible taste is the precise reason why the “lemon face challenge” is taking off. Participants bite into a lemon, taking a selfie as they do it before posting the photo online. The fun is all about expression people make as all that citric acid (柠檬酸) hits their taste buds (味蕾). Every expression seems to say, “This is worse than freezing water.”

    The serious side to this trend is the good cause it's all in aid of. The challenge aims to raise awareness of a rare brain cancer that affects young children. It was started by Aubregh Nicholas, an 11-year-old US kid. She was diagnosed with this rare brain cancer herself in September 2017, but has since raised almost $50000 to cover her medical expenses thanks to the challenge.

    If a challenge is going to raise publicity and contributions from people, it has to be something interesting and original. That way the ice bucket challenge took off in 2014 and it explains why so many people are now sharing their lemon faces. There are a lot of stories about the downside of social media these days. The charity challenges, however, show how online culture can unite the world and bring help to the people who most need it.

    John Winston Ono Lennon (9 October 1940-8 December 1980) was an English rock musician, singer, songwriter, artist and peace activist who gained worldwide fame as one of the founders of The Beatles. As a member of the group, Lennon was one of the leading singers and co-wrote most of the band's songs with bassist(低音歌手) Paul McCartney.

    In his singing career, Lennon wrote and recorded songs such as Give Peace a Chance and Imagine. Lennon showed his rebellious(反叛的) nature and cleverness on television, in films such as A Hard Day's Night, in his books such as In His Own Write, and in press conferences(新闻发布会) and interviews. He was controversial(有争议的) through his work as a peace activist, artist and author.

    Lennon had two sons: Julian Lennon, with his first wife Cynthia Lennon, and Sean Ono Lennon, with his second wife, avant-garde(前卫) artist Yoko Ono. After a retirement from 1976-1980, Lennon reemerged(再度出现) with a comeback album, but was killed one month later in New York City on 8 December 1980. In 2002, respondents to a BBC poll(投票) on the 100 Greatest Britons voted Lennon into the eighth place. In 2004, Rolling Stone magazine ranked Lennon number 38 on its list of "The Immortals(不朽的): The Fifty Greatest Artists of All Time" and ranked The Beatles number one.

    Being an astronaut sounds cool, doesn't it? In space, they get to do some pretty amazing things, like floating (漂浮) in zero gravity(重力).

    However, there are also plenty of things that astronauts can't do because of their weightless environment(环境), and that's very sad. What's worse, they can't even let their sadness show -because it's impossible to cry in zero gravity.

    Of course, astronauts can still produce tears. But crying is much more difficult in space, reported The Atlantic in January. Without gravity；tears don't flow downward out of the eyes like they do here on Earth. This means that when you cry in space, your tears have nowhere to go — they just stick to your eyes.

    In May 2011, astronaut Andrew Feustel experienced this during one of his spacewalks. "Tears," he said, "don't fall off your eye...They just kind of stay there."

    Besides making your vision(视觉) unclear, this can also cause physical pain. Back on Earth, tears are supposed to bring comfort to the eyes. But that's not the case in space. The space environment dries out astronauts' eyes, and when tears suddenly wet the eyes, it can cause pain rather than comfort. "My right eye is painful like crazy." Feustel told his teammate during the walk.

    Since gravity doesn't work in space, astronauts need some extra help to get rid of the tears. Feustel chose to rub his eyes against his helmet to wipe the tears away. Another choice is to just wait — "When the tears get big enough they simply break free of the eye and float around," astronaut Ron Parise told The Atlantic.

    There are lots of small things — things like crying — that we are so used to on Earth, we usually take them for granted, until they become a problem in a totally different environment, like space. There, astronauts can't talk to each other directly. They also can't eat or drink in normal ways. They can't even burp (打嗝), because there is no gravity to hold the food down in their stomach. If they do burp, they just end up throwing up (呕吐) everything in their stomach, according to the UK National Space Center.

    Thus, perhaps it's only space explorers who can honestly say, "Gravity, you're the best."

    Babies born in summer are more likely to become short-sighted in late life, a study has shown.

    As many as a quarter of all cases of short-sightedness are caused by too great an exposure to sunlight in the first weeks of life, say eye experts.

    They are advising all parents to put sunglasses on their babies during the first weeks.

    Scientists had already established that over-exposure to sunlight caused shortsightedness in animals.

    Researchers who compared the months in which babies were born with whether they needed glasses later on say the principle also applies to humans.

    A study of almost 300, 000 young adults-the largest of its kind-showed that those born in June and July had a 25 per cent greater chance of becoming severely short-sighted than those born in December or January.

    Research leader Professor Michael Belkin, of Tel Aviv University, said it was because prolonged illumination(光照) causes the eyeball to lengthen-causing short-sightedness.

    Hence the more light a newborn is exposed to, the more the eyeball lengthens and the worse the short-sightedness will be.

    The mechanism which lengthens the eyeball is associated with levels of melatonin(褪黑激素), a pigment (色素) which protects the skin against harmful rays of the sun.

    In young babies not enough melatonin is released as protection, meaning they are more vulnerable to sunburn and changes to eyeball shape.

    Sight expert Professor Daniel O'Leary, of Anglia Ruskin University in Cambridge, said "At the moment we don't know the precise cause of why light exposure affects sight, but the evidence seems to prove that it is one of the reasons for people becoming shortsighted."