Is there a magic cutoff period when offspring become accountable for their own actions? Is there a wonderful moment when parents can become spectators (旁观者) in the lives of their children and shrug, "It' s their life," and feel nothing?

    When I was in my twenties, I stood in a hospital corridor waiting for doctors to put a few stitches in my son's head. I was asked, "When do you stop worrying?" A nurse said, "When they get out of the accident stage." My mother just smiled faintly and said nothing.

    When I was in my thirties, I sat on a little chair in a classroom and heard how one of my children talked incessantly, disrupted (打断) the class, and was headed for a career making license plates. As if to read my mind, a teacher said, "Don't worry. They all go through this stage, and then you can sit back, relax, and enjoy them." My mother listened and said nothing.

    When I was in my forties, I spent a lifetime waiting for the phone to ring and the cars to come home, the front door to open.

    My friends said that when my kids got married I could stop worrying and lead my own life. I wanted to believe that, but I was haunted by my mother' s wan ( 淡淡的 ) smile and her occasional words, "You look pale. Are you all right? Call me the minute you get home."

    Can it be that parents are sentenced to a lifetime of worry? Is concern for one another handed down like a torch to blaze the trail of human frailties and the fears of the unknown? Is concern a curse? Or is it a virtue that elevates us to the highest form of life?

    One of my children became quite irritable recently, saying to me, "Where were you? I've been calling for three days, and no one answered. I was worried!!!"

    I smiled a wan smile.

    THURSDAY, July 9 (Health Day News) — A new study that found that a lower calorie diet slowed the aging process in monkeys could be the best proof yet that restricted diets might do the same for humans.

    “The big question in aging research is, ‘Will caloric restriction in species closely related to humans slow aging？'” said Richard Weindruch, senior author of a paper appearing in the July 10 issue of Science. This is the first clear demonstration that, in a primate species, we' re inducing a slowdown of the aging process — showing increased survival, resistance to disease, less brain atrophy and less muscle loss.

    “This predicts humans would respond similarly，” added Weindruch, professor of medicine at the University of Wisconsin and an investigator at the Veterans Hospital in Madison. Another expert noted that, despite some highly publicized studies in certain species, the link between restricted eating and longer lifespan has been far from proven.

    “The idea that dietary restriction extends lifespan in all species is not true. Many strains of rats and mice do not respond. In some strains, it's actually deleterious,” explained Felipe Sierra, director of the biology of aging program at the US National Institute on Aging (NIA), which supported the new study. “The fact that it doesn't work in some mice but it does seem to work in monkeys is surprising and it gives us hope.”

    But there's a larger question: how to change humans' increasingly careless eating habits. “This finding doesn't give me hope that humans are going to go into dietary restriction,” added Marianne Grant, a registered dietitian at Texas A&M Health Science Center Coastal Bend Health Education Center in Corpus Christi.

    On April 8th, 2013, the world felt sorry because of the death of former British Prime Minister, Margaret Thatcher, who died at the age of 87. Besides being the country's longest leader (1979-1990) in the 20th century, she was the first woman to lead Britain. She worked hard and did well in her work, so she was called" Iron Lady".

    Whatever you think of Margaret Thatcher, the thing everyone does agree on is that she was a woman with great decisions. When she took over Britain in 1979, she led a country that was in economic trouble. She faced a lot of problems because of the poor economic position.

    In order to make the country become strong again, Ms. Thatcher had to make some hard and special decisions like raising interest rates and even taxes at a time when most British people were living a hard life. In this way she led Britain to run out of economic troubles.

    Early in her second term, just as things were looking a little better, she faced another problem — a strike by the British Miners Union. Once again, the Iron Lady stood her ground to stop the longest strike in the country's history.

    In 1982, Argentina said that they had owned the Falkland Islands since the 19th century. Britain, however, considered the islands to be one of their overseas dependent territories (领土). Margaret Thatcher tried to talk about the problem with Argentines. But Argentines didn't agree with her ideas, so Ms. Thatcher did what any strong leader would do — send in the British Army. It took 74 days, and on 14th June 1982, the Argentine army finally failed and Britain controlled the Falkland Islands again.

    When Ms. Thatcher resigned in 1990, she left behind a country that was very strong. Unluckily, during the last few years of her life, something was wrong with her mind. She hardly remembered anything that was happening around her and even what she had done during her wonderful lifetime.

    Many people have long dreamed of being able to fly around as simply as riding a bicycle. Yet the safety and strength of a flying bike was always a big problem. Over the past 10 years, developments in technology have moved the dream of personal flying vehicles closer to reality. Now, two groups of inventors say such vehicles may be available soon.

    The British company Malloy Aeronautics has developed a prototype (原型) of its flying bicycle. Grant Stapleton, marketing sales director of Malloy Aeronautics, says the Hoverbike is able to get in and out of small spaces very quickly." It can be moved across continents very quickly because it can be folded and packed," he adds.

    Mr. Stapleton says safety was the company's main concern. He says the designers solved the safety issue by using overlapping rotors to power the vehicle.

    The company is testing a full-size prototype of the Hoverbike, which will most likely be used first by the police and emergency rescue teams.

    In New Zealand, Martin Aircraft Company is also testing a full-size prototype of its personal flying device, called the Jetpack. It can fly for more than 30 minutes, up to 1, 000 meters high and reach a speed of 74 kilometers per hour.

    Peter Coker is the CEO of Martin Aircraft Company. He said the Jetpack "is built around safety from the start". In his words, "Reliability is the most important element of it. We have safety built into the actual structure itself, very similar to a Formula One racing car.

    The Jetpack uses a gasoline-powered engine that produces two powerful jet streams. Mr. Coker says it also has a parachute that would be used, if there should be an emergency. "It starts to work at very low altitude and actually saves both the aircraft and the pilot," he adds. Mr. Coker says the Jetpack will be ready for sale soon.

    Teenagers who spend hours in front of the television may have a poorer diet as young adults.

    A study, which included nearly 1, 400 high school students, found those who watched TV for five hours or more per day had less healthy diets than peers (同龄人) five years later. Why does this happen? Should the parents take any measures?

    On the one hand, people who spend a lot of time in front of the TV, especially teenagers, may snack more, and that may affect their long-term diet quality.

    On the other hand, TV ads for fast food, sweets and snacks tempt teenagers to eat more of those foods. And TV time might also replace exercise time for some kids.

    Lead researcher Dr. Daheia J. Barr-Anderson, of the University of Minnesota in Minneapolis, told Reuters Health a clear correlation between TV time during high school and diet quality in young adulthood. While the heaviest TV viewers were eating the most junk food, those who'd watched less than two hours per day had the highest intake (吸收) of fruits, vegetables, whole grains and high-calcium food. In her opinion, parents should limit and monitor TV viewing.

    As far as I am concerned, children should watch no more than two hours of television per day. And parents should set a good example by eating right, being physically active and curbing their own TV time.