More and more people like bicycling and it is no surprise. It is fun, healthy and good for the environment. Maybe that's why there are 1.4 billion bicycles and only 400 million cars on roads worldwide today. Bikes can take you almost anywhere, and there is no oil cost!

    Get on a bicycle and ride around your neighbourhood. You may discover something new all around you. Stopping and getting off a bike is easier than stopping and getting out of your car.

    You can bike to work and benefit (受益) from the enjoyable exercise without polluting  the environment. You don't even have to ride all the way. Folding (折叠) bikes work well for people who ride the train. Just fold the bike and take it with you. You can do the same on an airplane. A folding bike can be packed in a suitcase. You can also take a common bike with you when you fly. But be sure to look for information by getting on airline websites. Not all airlines are bicycle-friendly to travellers.

Health Benefits of Bicycling:

    It helps to prevent heart diseases.

    Bicycling helps to control your weight.

    A 15-minute bike ride to and from work three times a week burns off five kilos of fat in a year.

    Bicycling can improve your mood (心情).

    Exercise like bicycling has been shown to make people feel better, more relaxed and self-confident.

    Bicycling is healthier than driving.

    A bite from a tsetse fly (采采蝇) is an extremely unpleasant experience. It is not like a mosquito, which can put its thin mouthpart directly into your blood, often without you noticing. In contrast, the tsetse fly's mouth has tiny saws on it that saw into your skin on its way to suck out your blood.

    To make matters worse, several species of tsetse fly can transmit diseases. One of the most dangerous is a parasite that causes ＂sleeping sickness＂, or ＂human African trypanosomiasis＂to give it its official name. Without treatment, an infection is usually fatal.

    Like so many tropical diseases, sleeping sickness has often been neglected by medical researchers. However, researchers have long endeavored to understand how it avoids our bodies' defence mechanisms. Some of their insights could now help us eliminate sleeping sickness altogether.

    There are two closely-related single-celled parasites that cause this deathly sleep: Trypanosoma brucei rhodesiense and T. b. gambiense. The latter is far more common: it is responsible for up to 95% of cases, mostly in western Africa. It takes several years to kill a person, while T. brucei rhodesiense can cause death within months. There are still other forms that infect livestock.

    After the initial bite, sleeping sickness symptoms often start with a fever, headaches and aching muscles. As the illness goes on, those infected become increasingly tired, which is where it gets its name. Personality changes, severe confusion and poor coordination can also happen.

    While medication does help, some treatments are toxic and can themselves be deadly, especially if they are given after the disease has reached the brain.

    It is worth noting that sleeping sickness is no longer as deadly as it once was. In the early 20th Century several hundred thousand people were infected each year. By the 1960s the disease was considered ＂under control＂ and had reached very low numbers, making its spread more difficult. But in the 1970s there was another major epidemic, which took 20 years to control.

    Since then, better screening programmes and earlier interventions have reduced the number of cases dramatically. In 2009 there were fewer than 10,000 cases for the first time since records began, and in 2015 this figure dropped to fewer than 3,000, according to the latest figures from the World Health Organisation. The WHO hopes the disease will be completely eliminated by 2020.

    While this decline looks positive, there may be many more cases that go unreported in rural Africa. To eliminate the disease completely, infections have to be closely monitored.

    More problematically, a series of new studies have shown that the parasite is more complicated than previously believed.

    Sleeping sickness has always been considered —— and diagnosed —— as a blood disease, because T. brucei parasites can readily be detected in the blood of its victims.

    From July to October every year, about a quarter of the world's blue whales feed in the Pacific Ocean off the coast of California. But the whales currently face a major threat in their favorite feeding area. Ships carrying cargo （货物）sail in the same area at the same time. All too often, the whales' paths and the ships' travel lines overlap (重叠), and a ship will hit a whale.

    According to a new study, these ship strikes have become a serious threat to the overall population of the world's blue whales. Only about 10,000 of the creatures still exist worldwide. Blue whales are the largest known animals ever to live on Earth. Even so, if hit by a container ship, a blue whale will likely die from its injuries.

    In 2007 alone, large ships killed five blue whales in the waters off San Francisco and Los Angeles, California. The National Oceanic and Atmospheric Administration (NOAA) says that because there are so few whales already, losing three to five from the California whale population every year is a significant loss. "The estimated population of blue whales in this part of the Pacific is 2,500", says Sean Hastings, a NOAA analyst. "So every whale counts toward this species moving off the endangered-species list."

    Now, marine scientists must figure out how to protect the whales from the giant container ships. One very simple program is already under way in the Santa Barbara Channel, a waterway that separates mainland California from the nearby Channel Islands.

    The Channel Islands National Marine Sanctuary has asked large container ships passing through the area to voluntarily slow down. Sailing slower will allow the ships crew （船员）more time to change course before hitting a whale.

    Several of the world's largest shipping lines are set to participate in the new program. For every ship that passes through the Santa Barbara Channel at or below the reduced speed of 12 knots （海里/小时）, the company that owns the ship will be paid $2,500.

    On a recent spring morning. Susan Alexander, a retired government intelligence analyst, left her Maryland home, climbed into her Volkswagen Passat and drove about three miles to pick up two strangers. She battled rush-hour traffic on the Capital Beltway and George Washington Memorial Parkway before dropping them off at Reagan National Airport. She didn't earn a cent for her trouble, and that was the point.

    Alexander is a member of the Silver Spring Time Bank-one of more than 100 such exchanges around the world trying to build community by exchanging time credits for services instead of dollars and cents. "I have time," she said. "I like giving the gift of time to other people."

    In Alexander's case, passengers Mary and Al Liepold were grateful for the ride, but it wasn't charity. Mary, a retired writer and editor for nonprofit organizations, used time credits she banked for editing work and baking. Senior citizens who don't drive, the Liepolds cashed in their credits to catch a flight to Montreal for a five-day vacation.

    Without money changing hands or shifting between virtual accounts, the airport drop-off was more like a coffee party than a taxi ride. Driver and passengers chatted about projects they've completed for the time bank, and no one raised an eyebrow when Mary said she likes "to avoid the conventional economy."

    "The beauty of this is that you make friends," Mary Liepold said. "You don't just get services."

    The Silver Spring Time Bank formed in 2015 and has about 300 members, said co-founder Mary Murphy. Last year, she said, l,000 hours were exchanged for basic home repairs, dog walking, cooking and tailoring, among other services, without the exchange of money. "You get to save that money that you would have spent," she said. "You get to meet somebody else in your community and get to know that person. That's a bonus that's part of an exchange."

    A deal performed partly to make friends would seem to go against classical economics and one of Benjamin Franklin's most memorable sayings: "Time is money." To those at the forefront of modem time-banking, that is the appeal.

    A nation's humor is linked to the historical development of the country. How funny somebody finds a certain thing depends on many things including ages, personal experiences, levels of education and locations. Therefore, humor is something that is not always transferable (可转移的) in another country.

    What about when both countries speak the same mother tongue? Does that mean they will then share the same sense of humor, or can differences still take place? Let's take the example of Britain and America. Time and time again, people say that Brits and Americans don't "get" each other's sense of humor. It is often argued that one of the most common differences between the British and American sense of humor is that Americans don't understand irony (反话). Simon Pegg explores this topic in depth in his article What Are You Laughing At? He concludes that this statement isn't true and I agree with him.

    In fact, Brits use irony on a daily basis while Americans don't. I think Americans understand British irony (most of the time anyway); what they don't understand is the need to use it so frequently. When Americans use irony, they tend to say that they are "only kidding". They feel the need to make a joke more obvious than Brits do. Maybe this comes from a fear of offending (冒犯) people.

    The American sense of humor is generally more slapstick (闹剧的) than that in Britain. I think this arises from a cultural difference between the two. Their jokes are more obvious and forward, a bit like Americans themselves. British jokes, on the other hand, tend to be more subtle. This may stem from the fact that British culture is more reserved (矜持的) than American culture.

    A few weeks ago, I sat with a California farmer named Dave Ribeiro. I asked him what he wished to know about farmers. He smiled and said, "That we walk among you. We look like you and talk like you. We have advanced degrees and hobbies, just like you."

    Take Dave for example: He's a young man with a music degree. And if you walked past him on the street, you'd never think, "There goes a farmer."

    Is someone like Dave who you picture when you think of a farmer? Probably not. I think that most people would picture a man in his overalls(工作服). I can tell you, that does not represent Dave or any of the many other farmers I have gotten to know.

    Not only do we have to throw out our previous impression of farmers, but farming as a whole doesn't look much like it used to either. We recently sent a team out to see what modern farming looks like, and they found farmers to be completely different from our usual ideas about them and also came across them in some unexpected places.

    In a parking lot in a neighborhood of Brooklyn, they met a new crop of young farmers who were trying to bring fresh greens closer to eaters in the city by growing them in high-tech indoor vertical(垂直的) farms. In a Florida field under the fight path of an airport, they discovered farmers with university degrees growing plants that might someday fuel our cars. And in a modern farm in California, they observed how farmers were using technology to take the best possible care of their animals.

    These farmers all spend their days in very different ways—none of them looks like the previous farmer we have in our mind—but they're all working on new ways to feed our planet. Not only do we need to change our idea of what farming looks like, but we also need to change our view of where solutions can come from. Feeding all of us is going to take all of us working together.