One Sunday, my son asked me if he could ride up to his elementary school on his bike and meet his friend. He wanted both of them to ride back to our house so they could play video games and jump on the trampoline (蹦床). I have to admit, part of me wanted to say no. We could go to pick him up or his parents could bring him over here. I thought. But my son is eleven years old now. And after all, I do let him ride his bike to school. But I also drive my daughter to school and I can see him on the way, making sure he is getting there safely.

    My husband thinks I am overprotective. I don't dare to let my children walk anywhere without one of us going along. As you go out of our neighborhood, there is a shopping center across the street. My son always asks if he can ride his bike or walk over to the drugstore by himself. But crossing that street is just too dangerous. The cars fly around the comer like they're driving in a car race. What if he gets hurt? What if some teenager bullies are hanging out in the parking lot? I want so much to give my children the freedom that I enjoyed having when I was growing up but I hesitate to do so, because there are dangers around every comer. Too many kidnap, too many robberies and so on.

    I honestly don't think my mom worried about such things when her children were young. Growing lip in the 1970s was indeed very different. I never wore a helmet (头盔) when I rode a bike. We were all over the neighborhood, on our bikes and on foot, coming home for dinner and then-back out again until dark. We rode in the back of the truck and didn't wear seat belts. I walked to and from school every day.

    Running seems easy enough: Just grab a pair of sneakers and put one foot in front of the other, right? Well, anyone who struggled to get through a mile knows it's not quite that simple. We've asked experienced runners to tell us something wrong they did when they started running. The following are some of their answers.

    I got excited and signed up for a half-marathon with a few more experienced runner friends, but I wasn't adequately prepared and didn't train efficiently. I ended up with blisters(水泡) on my feet. I couldn't wear shoes for two days!

—Cali Lavey

    I have always been athletic and I have never been badly injured, but one day I felt a slight pain in my knee. I ignored it for a month until I realized I was having a hard time putting weight on my right leg. I finally went to a doctor. It took four months of weekly physical therapy(治疗) to heal. I shouldn't have done that.

— Arnold

    My biggest mistake was treating running like soccer practice: If I wasn't exhausted by the end of practice, I felt as though I didn't work hard enough. I run all of my runs at 80 percent effort, or the equivalent of what I now call tempo runs (节奏跑). I wasn't warming up to the pace or cooling down effectively.

— Kate

    I decided to go out for a run during the hottest part of the day. At the time, I told myself that it would be refreshing to sweat a little, but I didn't bring adequate water. I returned feeling completely rundown, dehydrated (脱水的), and exhausted. If you must go out on a run during unfavorable weather, wear proper suits and bring enough water to keep you feeling strong.

— Sarah

    The day will come when renewable energy such as wind, solar, geothermal and others replace fossil fuels as the major source of world energy. However, most analysts insist that this day will not arrive for many decades to come—certainly well past the middle of the century. Systems of fossil fuels have already been firmly set up, and it is too costly or impractical to replace the existing systems with renewables. But there are good reasons to believe that the transition (转变) to renewables will come much faster than previously thought.

    It is hardly surprising that many experts say we will see a relatively slow transition from fossil fuels to renewables, given what is known about previous energy changes of this sort. "Energy transitions take a long time," observed Vaclav Smil of the University of Manitoba in Scientific American. It took more than 50 years for coal to replace wood as the world's leading source of energy and another 50 years for oil to replace coal; the change from fossil fuels to renewables, he argued, is not likely to come any faster.

    Under ordinary circumstances, Smil's forecast would no doubt prove accurate. But these are not ordinary times. Growing concern over climate change is leading to increasingly strict controls on CO₂ and other greenhouse gas (GHG) emissions (排放), while the development in renewables technology is lowering their price and speeding their installation.

    There are, of course, many difficulties in the effective control of carbon emissions, as demonstrated by coal companies to block the introduction of new rules by the US Environmental Protection Agency. Nevertheless, it is impossible to dismiss the progress being made at the local and international levels to promote the use of renewables. The European Union (E. U), for example, is well on the way to achieving a 20% reduction in GHG emissions from 1990 levels by 2020, along with a 20% increase in the use of renewable energy.

    The transition to renewables will be faster due to dramatic improvements in the pricing and performance of such systems. As a result of the steady increases in the efficiency of wind and solar systems, together with the savings achieved through large-scale manufacture, the price of renewables is falling globally. With prices dropping this fast, solar energy is now proving competitive with fossil fuels for generating electricity in many areas.

    The change from fossil fuels to renewable energy will not come overnight, and it will not escape many setbacks. Nevertheless, renewables are likely to replace fossil fuels as the main source of electrical power well before mid-century.

    When he was a kid, Alex Vardakostas began working in the grill (烧烤店)alongside adult employees. He estimates he has cooked 50,000 burgers (汉堡包).

    Now, Vardakostas co-owns a burger joint called Creator, in San Francisco, California. But he doesn't stand over a grill flipping burgers, and neither do his employees. At Creator, burgers are cooked and assembled entirely by machine. And because it costs less to maintain the machine than to pay a kitchen's worth of employees, burgers cost less.

    Creator is just one example of a growing phenomenon: Automation is taking over more and more jobs. That means work is done by machines or computers instead of people.

    According to a report from McKinsey Global Institute, about 800 million people could be forced out of their jobs by 2030. McKinsey predicts that as technology improves, some tasks will be done more quickly or cheaply by machine, so businesses will install robots or computer Programs to perform them.

    Some jobs are more likely to be automated than others. Machines can do jobs that have three characteristics: They are routine, repetitive, and predictable. Some of these jobs pay low wages and require little education. But others pay well and demand an advanced college degree. Taxi drivers, cashiers, lawyers, and doctors all perform some tasks that can be done by machines.

    So what jobs are safe from automation? Answers include coming up with new ideas or work that involves interacting with other people and building relationships. Jobs in engineering, science, the arts, therapy, and nursing are examples.

    At Creator, Vardakostas hired people to do just that kind of work. Instead of repetitive burger prepping, workers interact with customers and advise them on flavor pairings, like mushroom sauce with pickles and onion jam. "In our world at Creator, all the work is creative and social," Vardakostas says. "And I think that is what we're going to see more of the future."

    Frogmore House has been a royal place since the 18th century and is today used by the Royal Family for private entertaining. It is especially linked with Queen Charlotte, The wife of George III, and her daughters, whose love of botany and art is reflected throughout the house.

    Unfortunately, parts of a visit to Frogmore are unsuitable for wheelchair-users. For information about access, please telephone 020 7766 7324.

Frogmore House and Garden

    18, 19, 20 May 10:00 - 17:30 (last admission 16:00)

    28, 29, 30 August 10:00 -17:30 (last admission 16:00)

    Please telephone 020 7766 7305 for admission prices.

    Summer Opening for Pre-booked Coach Groups

    3 August - 30 September every Tuesday, Wednesday, Thursday and Saturday, 10:00- 15:00.

    Adult: £ 10.50 0ver 60/Student (with valid ID): £ 8. 80

    Child (under 17) : £5. 80 Child (under 5): Free

    Price includes a guided tour of the house.

    Private Evening Tours

    17:30 - 19:00. £25. 00 per person. Price includes a guided tour, a copy of the official guidebook and a glass of champagne.

    The maximum group size for all visits is 10 people

    Please note that there is no access for private cars.

    To make a group booking, please telephone 020 7766 7315.

    For more information including BSL (British Sign Language) interpretation, please telephone 020 7766 7326.

    In its early history, Chicago had floods frequently, especially in the spring, making the streets so muddy that people, horses, and carts got stuck. An old joke that was popular at the time went something like this: A man is stuck up to his waist in a muddy Chicago street. Asked if he needs help, he replies, "No, thanks. I've got a good horse under me."

    The city planner decided to build an underground drainage （排水） system, but there simply wasn't enough difference between the height of the ground level and the water level. The only two options were to lower the Chicago River or raise the city.

    An engineer named Ellis Chesbrough convinced the city that it had no choice but to build the pipes above ground and then cover them with dirt. This raised the level of the city's streets by as much as 12feet.

    This of course created a new problem: dirt practically buried the first floors of every building in Chicago. Building owners were faced with a choice: either change the first floors of their buildings into basements, and the second stories into main floors, or hoist the entire buildings to meet the new street level. Small wood-frame buildings could be lifted fairly easily. But what about large, heavy structures like Tremont Hotel, which was a six-story brick building?

    That's where George Pullman came in. He had developed some house-moving skills successfully. To lift a big structure like the Tremont Hotel, Pullman would place thousands of jackscrews (螺旋千斤顶) beneath the building's foundation. One man was assigned to operate each section of roughly 10jackscrews.At Pullman's signal each man tured his jackscrew the same amount at the same time, thereby raising the building slowly and evenly. Astonishingly, the Tremont Hotel stay open during the entire operation, and many of its guests didn't even notice anything was happening.

    Some people like to say that every problem has a solution. But in Chicago's early history, every engineering solution seemed to create a new problem. Now that Chicago's waste water was draining efficiently into the Chicago River, the city's next step was to clean the polluted river.