The term “to extend an olive（橄榄） branch” means to make an offer of peace or reconciliation(和好). This term has Biblical（圣经的）origins, coming from the section of the Old Testament that deals with the flood; the sign that the flood is over is an olive branch brought back to the ark(方舟) by a dove. Olive branches were also symbols of peace in Ancient Greece and Rome, and they continue to be used in various works of art that are meant to suggest peace.

    Some people have suggested that the olive was a very deliberate and well-considered choice as a metaphor(比喻）for peace, because olive trees famously take years to mature. War is typically very hard on the trees because people cannot take the time to nurture them and plant new ones. Therefore, the offer of an olive branch would suggest that someone is tired of war, whether it is an actual war or a falling out between friends.

    In Ancient Greek and Roman times, people would offer actual olive branches. In Rome, for example, defeated armies traditionally carried olive branches to indicate that they were giving in, and the Greeks used them into weddings and other ceremonies. In the modern era, the branch is usually metaphorical, rather than actual, not least because the plants can be a bit difficult to obtain.

    Many people agree that peace negotiations at all levels of society are a good idea. Between nations, obviously, it is important to extend an olive branch to ensure mutual safety and to help the world run more smoothly. This act can also be important on a personal level, as resolving conflict and learning to get along with others is viewed as an important life skill in many cultures.

    At some point in their lives, many people will be advised to extend an olive branch to settle a dispute or resolve an issue. Some people believe that it takes an immense amount of courage to take this action, as it often comes with an admission of wrongdoing and regret.

    English is the most widely used language in the history of our planet. One in every seven human beings can speak it. More than half of the world's books and three quarters of international mail are in English. Of all languages, English has the largest vocabulary — perhaps as many as two million words.

    However, let's face it: English is a crazy language. There is no egg in an eggplant, neither pine nor apple in a pineapple and no ham in a hamburger. Sweet-meats are candy, while sweetbreads, which aren't sweet, are meat.

    We take English for granted. But when we explore its paradoes (探索它的矛盾), we find that quicksand can work slowly, boxing rings are square, public bathrooms have no baths in them.

    And why is it that a writer writes, but fingers don't fing, grocers don't groce, and hammers don't ham? If the plural of tooth is teeth, should't the plural of booth be beeth? One goose, two geese — so one moose, two meese?

    How can a slim chance and a fat chance be the same, while a wise man and a wise guy are opposites? How can overlook and oversee be opposites, while quite a lot and quite a few are alike? How can the weather be hot as hell one day and cold as hell the next?

    English was invented by people, not computers, and it reflects the creativity of human beings. That's why, when stars are out, they are visible (能看见的); but when the lights are out, they are invisible. And why, when I wind up my watch, I start it; but when I wind up this essay, I end it.

    People who like travelling have their reasons. They believe that travelling can help them expand their field of view, especially in the geographical and historical sense. They also think that touring will give them more chances to enjoy different kinds of food and experience new things that would never be brought by other activities. But those who dislike travelling also have some reasons.

    Travelling, in my opinion, does more good than harm. Most importantly, it broadens  (使扩大) our mind. We can get in touch with other civilizations (文明), cultures, customs and ideas.

    Through history, most people travelled because of necessity (必要性)—not for pleasure. People travelled just in order to remain alive. They searched for food to eat or places to live in. They sometimes ran away from enemies. This is not to say that no one ever travelled just for the fun of it. In ancient times, for example, rich Romans travelled all the way to Greece to take part in the Olympic Games, and festivals. Of course, some people decided to travel just out of curiosity (好奇心). They wanted to find out what it looked like beyond the horizon (地平线). Also business travel has been going on for centuries. Traders could not only make money but also learn to speak several languages and be introduced to different cultures.

    So, travelling does enrich our mind and draw new ideas to us. There is no doubt that we can get much from it.

    Last week, two companies, Kitty Hawk and Uber, announced their plans to bring flying cars to reality very soon.

    Imagine never having to worry about traffic, stop lights, or road construction. A flying car would get to a place much faster than one travelling by road. On the other hand, imagine having to avoid drones (无人驾驶飞机) and other flying cars. Also, what if your battery dies when you are in the air? And, how will you know where to land?

    Kitty Hawk is a start-up tech company supported by Google co-founder, Larry Page. According to the Kitty Hawk website, its car will be able to travel at speeds up to 40 kilometers an hour in the air. It says under US aviation law such a machine “does not require registration or a pilot's license and may be flown in uncongested (不拥挤的) areas for recreational purposes.” As of now, the car can only be flown over fresh water.

    Kitty Hawk is making a list of people interested in buying the flying car. They must pay a deposit of US$100. Those who get their names on the list early will receive US$2, 000 off the final cost of the car. However, Kitty Hawk has not yet announced the price. Kitty Hawk expects its first flying cars will go on sale by the end of this year.

    At a conference last week, Uber announced plans for flying taxis to begin carrying passengers. Unlike the Kitty Hawk company, Uber does not plan to build its flying cars. Instead, it will use the resources of partner companies.

    Like the Kitty Hawk car, Uber flying taxis will use electric power. Uber says its flying taxis could travel up to 241 kilometers an hour. The company said that could reduce the travel time between San Francisco and San Jose, California from two hours on the road to 15 minutes in the air.

    Riders could use the Uber app to book a flying taxi to take them to their destinations. The company has not yet said how costly air taxi travel would be compared to road taxi travel.

Keeping secrets is a burden

    “Don't tell anyone”. We hear these words when someone tells a secret to us. But it can be hard to keep a secret. We're often tempted to “spill the beans(说漏嘴)”, even if we regret it later.

    According to Asim Shah, professor in the Menninger Department of Psychiatry and Behavioral Sciences at Baylor College of Medicine, US, keeping a secret may well “become a burden”. This is because people often have an “obsessive and anxious urge to share it with someone”.

    An earlier study, led by Anita E. Kelly, a scientist at the University of Notre Dame, US, suggested that keeping a secret could cause stress. People entrusted(受委托的) with secrets can suffer from depression, anxiety, and body aches, reported the Daily Mail.

    But with secrets so often getting out, why do people share them at all? Shah explained that people often feel that it will help them keep a person as a friend. Another reason people share secrets is guilt over keeping it from someone close to them. A sense of distrust can develop when people who are close do not share it with each other. “Keeping or sharing secrets often puts people in a position of either gaining or losing the trust of someone,” according to Shah.

    He added that talkative people could let secrets slip out (泄露).But this doesn't mean that it is a good idea only to share secrets with quiet people. A quiet person may be someone who keeps everything inside. To tell such a person a secret may cause them stress, and make them talk about the secret. Shah said that to judge whether to tell someone a secret.

    Shah said that to judge whether to tell someone a secret, you'd better put yourself in their position. Think about how you would feel to be told that you mustn't give the information away. Shah also recommended that if you accidentally give up someone's secret you should come clean about it. Let the person know that their secret isn't so secret anymore.

    It's common knowledge that the woman in Leonardo da Vinci's most famous painting seems to look back at observers, following them with her eyes no matter where they stand in the room. But this common knowledge turns out wrong.

    A new study finds that the woman in the painting is actually looking out at an angle that's 15.4 degrees off to the observer's right­well outside of the range that people normally believe when they think someone is looking right at them. In other words, said the study author, Horstmann, "She's not looking at you." This is somewhat ironic, because the entire phenomenon of a person's gaze (凝视) in a photograph or painting seeming to follow the viewer is called the "Mona Lisa effect" . That effect is absolutely real, Horstmann said. If a person is illustrated or photographed looking straight ahead, even people viewing the portrait from an angle will feel they are being looked at. As long as the angle of the person's gaze is no more than about 5 degrees off to either side, the Mona Lisa effect occurs.

    This is important for human interaction with on-screen characters. If you want someone off to the right side of a room to feel that a person on-screen is looking at him or her, you don't cut the gaze of the character to that side­surprisingly, doing so would make an observer feel like the character isn't looking at anyone in the room at all. Instead, you keep the gaze straight ahead.

    Horstmann and his co-author were studying this effect for its application in the creation of artificial-intelligence avatars(虚拟头像) when Horstmann took a long look at the "Mona Lisa" and realized she wasn't looking at him.

    To make sure it wasn't just him, the researchers asked 24 people to view images of the "Mona Lisa" on a computer screen. They set a ruler between the viewer and the screen and asked the participants to note which number on the ruler intersected Mona Lisa's gaze. To calculate the angle of Mona Lisa's gaze as she looked at the viewer, they moved the ruler farther from or closer to the screen during the study. Consistently, the researchers found, participants judged that the woman in the "Mona Lisa" portrait was not looking straight at them, but slightly off to their right.

    So why do people repeat the belief that her eyes seem to follow the viewer? Horstmann isn't sure. It's possible, he said, that people have the desire to be looked at, so they think the woman is looking straight at them. Or maybe the people who first coined the term "Mona Lisa effect" just thought it was a cool name.