In ancient Egypt, a shopkeeper discovered that he could attract customers to his shop simply by making changes to its environment . Modern businesses have been following his lead, with more tactics（策略）.

One tactic involves where to display the goods. For example, stores place fruits and vegetables in the first section. They know that customers who buy the healthy food first will feel happy so that they will buy more junk food later in their trip. In department stores, section is generally next to the women's cosmetics(化妆品) section：while the shop assistant is going back to find the right size shoe, bored customers are likely to wander over cosmetics they might want to try later.

Besides, businesses seek to appeal to customers' senses. Stores notice that the smell of baked goods encourages shopping, they make their own bread each morning and then fan the bread smell into the store throughout the day. Music sells goods, too. Researchers in Britain found that when French music was played, sales of French wine went up.

       When it comes to the selling of houses, businesses also use highly rewarding tactics. They find that customers make decision in the first few second upon walking in the door, and turn it into a business opportunity. A California builder designed the structure of its houses smartly. When entering the house, the customer would see the Pacific Ocean through the windows, and then the poll through an open stairway leading to the lower level. The instant view of water on both levels helped sell these $10 million houses.

    You may think, salt is just a simple cooking element we shake on our food for a little extra taste. But salt is much more than that. Without salt our muscles would not move. Our nervous systems would not operate. Our hearts would not beat.

    But do not think rubbing salt in a wound will help. Doing that would be painful and not heal the wound. To rub salt in a wound is an idiom that means to purposefully make a bad situation worse.

    Early humans got the salt they needed to stay alive from the animals they killed. But advances in agriculture led to a diet low in salt. So, humans needed to find other sources. Those who lived near the ocean or other natural sources for salt were lucky. Those who did not had to trade for salt. In fact, people used salt as a method of payment in many parts of the ancient world. The word “salary” comes from the word “salt”.

    Salt also played an important part in population movement and world exploration. Explorers understood that if they could keep food fresh, they could travel longer distances. So they used salt to preserve food and explored the world.

    Salt was so important that, according to food historians, it was traded pound-for- pound for gold. Today, people still use the expressions “to be worth one's salt” or “worth one's weight in salt”. The expressions describe a person of value.

    A person might also be called “salt of the earth”. That description means he or she is dependable and trustworthy. However, when you say “I think we should take what he said with a grain of salt” you mean you accept it but maintain a degree of doubt about its truth.

    Some people will do just about anything to save money．And I am one of them．Take my family's last vacation．It was my six­year­old son's winter break from school, and we were heading home from Fort Lauderdale after a week long trip．The flight was overbooked, and Delta, the airline, offered us $400 per person in credits to give up our seats and leave the next day．I had meetings in New York, so I had to get back．But that didn't mean my husband and my son couldn't stay．I took my nine­month­old and took off for home．

    The next day, my husband and son were offered more credits to take an even later flight．Yes, I encouraged — okay, ordered — them to wait it out at the airport, to “earn” more Delta Dollars．Our total take: $1,600．Not bad, huh?

    Now some people may think I'm a bad mother and not such a great wife either．But as a big­time bargain hunter, I know the value of a dollar．And these days, a good deal is something few of us can afford to pass up．

    I've made a living looking for the best deals and exposing（揭露）the worst tricks．I have been the consumer reporter of NBC's Today show for over a decade．I have written a couple of books including one titled Tricks of the Trade: A Consumer Survival Guide．And I really do what I believe in．

    I tell you this because there is no shame in getting your money's worth．I'm also tightfisted when it comes to shoes, clothes for my children, and expensive restaurants．But I wouldn't hesitate to spend on a good haircut．It keeps its shape longer, and it's the first thing people notice．And I will also spend on a classic piece of furniture．Quality lasts．

    On a clear night, you can see a sky paced with stars. But you can't see planets orbiting any of these stars, even with the strongest Earth—based telescopes. Astronomers reported that they discovered seven Earth—sized planets orbiting a nearby star called TRAPPIST – 1 in February. They had to rely on indirect evidence to tell them that the planets are there. By doing some math, they figured out the number of planets and the distance of their orbits.

    TRAPPIST – 1 is a red dwarf （红矮星）, much smaller than our sun, but larger than Jupiter (木星). If the sun were the size of a basketball, TRAPPIST – 1would be the size of a gold ball. This star is one of our closest neighbors, just like the moon to the earth in space.

    When astronomers using Earth-based telescopes to study TRAPPIST – 1,they noticed that every once in a while, it became slightly dim（昏暗）. They decided that a planet must be passing in front of the star, blocking part of the light. This dimming would come and go as the planet orbited the star, passing alternately (交替地) behind and in front of the star regularly.

    By making careful observations, astronomers expected to get a rough idea of the planet's size from the pattern of dimming light. But the light level changed often and not at evenly spaced (均匀间隔的) times. The astronomers had to conclude they were looking at more than one planet! To get additional data, NASA's spritzer Space Telescope measured TRAPPIST –1's brightness nearly continuously for 20 days, catching 34 crossings of planets in front of the star. Sorting through the mess of data, the astronomers found that the innermost planet completes its orbit in 1.5 Earth days, while the outermost planet takes 20 days. Once you know how long it takes each planet to complete an orbit, you can work out how far it is from the star compared with the other planets.

    The TRAPPIST – 1 planets are not alone. So far, astronomers have found more than 3,400 planets that orbit other stars.

    You're rushing to work and a man ahead of you collapses on the sidewalk. Do you stop to help? In a study of by-standers, it was found that some people avert their gaze and keep on walking rather than stop and get involved.

    "There is a tendency to decide that no action is needed." says a psychologist. "The first thoughts that pop into your mind often keep you from offering help. In order to take action, you have to work against them. " Here are some common thoughts that might prevent you from helping.

    Why should I be the one? I'm probably not the most competent (有能力的) person in this crowd. You might think someone older or with more medical knowledge should offer assistance.

    What if he doesn't really need my help? The fear of embarrassment is powerful; no one wants to risk looking foolish in front of others.

    No one else looks concerned—this must not be a problem. We can follow the people around us, but most people tend to hold back their emotions in public.

    "If you spot trouble and find yourself explaining inaction, force yourself to stop and assess the situation instead of walking on," says the psychologist. "Then retry to involve other people; you don't have to take on the entire responsibility of being helpful. Sometimes it's just a matter of turning to the person next to you and saying, 'It looks like we should do something.' Or asking someone if an ambulance has been called and, if not, to call for one. Once you take action, most people will follow you."

    Maybe it's because it was our first purchase as homeowners. The salesman must have spotted just how green we were, so he began persuading. And soon he led us to a classic leather chair. All these years later, I remember he used words like rich and handsome, the thing every living room needed.

    We believed him. So we bought that chair — just less than $100, a great deal in the 1970s for a young couple!

    How we loved that chair! It always occupied a place of honor in our various living rooms, moving with us from our first tiny house to our beloved new house.

    Somehow, conversations were better on that chair, and life was more fun around it. Three daughters spilled their secrets on it. Old friends seemed to be attracted by it on those wonderful occasions. Crazy as it sounds, that leather chair seemed to have — well, powers. All for good.

    At first, we didn't really care that the leather was showing signs of wear or that it had lost its sheen (光泽). But in our most recent move, when the chair was moved in our new living room, it suddenly looked terribly lonely sitting close to newly painted walls and a couple of shiny new tables.

    My husband and I tried but still we couldn't ignore the rough spots. Our chair had a skin disease. Even our adult kids raised eyebrows, urging us to at least remove the chair to some dark comer of the room. Neither of us could imagine such a retirement for it.

    So we had an inspired idea. We'd call in an upholsterer (修理工) to give our old chair a whole new life. Our friend Joe studied the chair and then took out a simple leather conditioner. He explained that although it wouldn't work miracles, it would definitely get our weary chair looking younger again. It certainly doesn't look new, but its seat and back are shining, and some of its deeper wrinkles have lightened.

    Best of all, it's back in the living room, looking like a wise old friend to the furniture around it. And, yes, there it will stay.

    Because some things, like some people, just deserve a happy old age.