"Have a nice day！" may be a pleasant gesture or a meaningless expression. When my friend Maxie says "Have a nice day" with a smile, I know she sincerely cares about what happens to me. I feel loved and safe since another person cares about me and wishes me well.

    "Have a nice day. Next！" This version of the expression is spoken by a salesgirl at the supermarket who is rushing me and my groceries out the door. The words come out in the same tone (腔调) with a fixed procedure. They are spoken at me, not to me. Obviously, the concern for my day and everyone else's is the management's attempt to increase business.

    The expression is one of those behaviors that help people get along with each other. Sometimes it indicates the end of a meeting. As soon as you hear it, you know the meeting is at an end. Sometimes the expression saves us when we don't know what to say. "Oh, you just had a tooth out? I'm terribly sorry, but have a nice day. "

    The expression can be pleasant. If a stranger says "Have a nice day" to you, you may find it heart­warming because someone you don't know has tried to be nice to you.

    Although the use of the expression is an insincere, meaningless social custom at times, there is nothing wrong with the sentence except that it is a little uninteresting. The salesgirl, the waitress, the teacher, and all the countless others who speak it without thinking may not really care about my day. But in a strange and comfortable way, it's nice to know they care enough to pretend they care when they really don't care all that much. While the expression may not often be sincere, it is always spoken. The point is that people say it all the time when they like.

    Thomas Edison was one of ten said to be the greatest genius of his age. There are only a few men in all of the history, who have changed the lives of other men as much as the inventor of the first useful electric light. But Edison could never be happy only because someone said he was a genius. “There is no such thing as genius,” Edison said. He said that what people called genius was mostly hard work.

    But Edison was a dreamer as well as a worker. From his earliest days as a child he wondered about the secrets of nature. Nature, he often said, is full of secrets. He tried to understand them; then, he tried to learn what could usefully be done with them.

    Edison enjoyed thinking. He knew that most people will do almost anything instead of the difficult work of thinking, especially if they do not think very often. But he knew, too, that thinking can give men enjoyment and pleasure.

    Edison could not understand how anyone could be uninterested in life. As he loved to think, he also loved to work. On the day he became 75 years old, someone asked him what ideas he had about life. “Work,” he answered. “Discovering the secrets of nature and using them to make men happier.” He said he had enough inventions in his mind to give him another 100 years of work.

    I live a different life in every season. Life in the summertime is often full of pests. Like most Long Island homeowners, I want to ensure my suburban life with pest-free living. So it was with wide-eyed surprise that I greeted the smiling exterminator (灭虫者) who rang my bell.

    “We'll be serving your neighbors, Mike and Sarah (I'm not familiar with either one by name),” he waved in the other direction. “Since we'll have a team here tomorrow, we're offering a discount. ” He came out with numbers beginning from $299 then in seconds to $89.

    “You've probably been seeing the ant hills around.” he moved toward my front walkway and lawn. “And have you seen the bees that dig nests in the ground?” he continued with his head shaking up and down pushing me to do the same.

    “What we do is spray three feet out from your foundation and three feet up.” As he was talking, and without breaking eye contact, he opened his iPad cover and began operating at the screen to show me frightening images. “It also kills other pests, like spiders. It is the best pesticide (杀虫剂),” he said, pausing for effect.

    He then went into soft talk to close the deal, correctly foreseeing that I would be concerned about safety and the environmental impact on my vegetable garden, plants and our little patch of planet here on Long Island. “The products are environmentally responsible, safe with children and pets,” he said.

    I'm unkind when it comes to unwanted visitors entering on my out-of-doors moments. Any insect found in my house or on my deck is bound to be poisoned or pancaked.

    Unfortunately for the exterminator, just as I was considering buying the pesticide, Billy, my fearless husband, pulled into our driveway, which made me ask for a business card out of politeness instead.

    Tiny Countries You Never knew Existed

    Sao Tome and Principe

    Sao Tome and Principe off Africa's west coast is only 372 square miles, but it has Impressive, undamaged nature, rich in biodiverse species. The amazing needle-like volcanic peak Pico Cao Grande rises 1,000 feet into the air. The islands are home to only around 200,000 people today.

    San Marino

    Only 23 square miles with a population of just 34,000, the little-known country of San Marino, surrounded by Italy, is the world's fifth smallest country. With the UNESCO World Heritage Site of Mount Titano, the country is said to be the oldest republic in the world.

    Dominica

    Dominica covers only 290 square miles, with some of the best diving in the Caribbean, including the UNESCO World Heritage Site of volcanic Morme Trois Pitons National Park. In Dominica, you'll see rainforests, waterfalls, and coastal views. The island is also home to the only remaining population of the Kalinago, who are part of the island's 74, 900 inhabitants.

    Kiribati

    This Pacific island country 33 coral islands is 313 square-miles, but it's the only country in the world to fall into all four hemispheres (半球). The country's 109, 000 residents live in only 21 of the islands see this tropical paradise before it is no longer--rising seas are threatening to swallow the country whole.

    When John was growing up, other kids felt sorry for him. His parents always had him weeding the garden, carrying out the garbage and delivering newspapers. But when John reached adulthood, he was better off than his childhood playmates. He had more job satisfaction, a better marriage and was healthier. Most of all, he was happier. Far happier.

    These are the findings of a 40-year study that followed the lives of 456 teenage boys from Boston. The study showed that those who had worked as boys enjoyed happier and more productive lives than those who had not. "Boys who worked in the home or community gained competence (能力) and came to feel they were worthwhile members of society," said George Vaillant, the psychologist (心理学家) who made the discovery. "And because they felt good about themselves, others felt good about them."

    Vaillant's study followed these males in great detail. Interviews were repeated at ages 25, 31 and 47. Under Vaillant, the researchers compared the men's mental-health scores with their boyhood-activity scores. Points were awarded for part-time jobs, housework, effort in school, and ability to deal with problems.

    The link between what the men had done as boys and how they turned out as adults was surprisingly sharp. Those who had done the most boyhood activities were twice as likely to have warm relations with a wide variety of people, five times as likely to be well paid and 16 times less likely to have been unemployed. The researchers also found that IQ and family social and economic class made no real difference in how the boys turned out.

    Working—at any age—is important. Childhood activities help a child develop responsibility, independence, confidence and competence—the underpinnings (基础) of emotional health. They also help him understand that people must cooperate and work toward common goals. The most competent adults are those who know how to do this. Yet work isn't everything. As Tolstoy once said, "One can live magnificently in this world if one knows how to work and how to love, to work for the person one loves and to love one's work."

    Imagine your body is like the house you live in. Every day, your family creates rubbish. The rubbish builds up until it is put out for the weekly garbage collection.

    Now, say you put three bags of garbage out, but because one of the collectors was away sick, only two bags are collected. You take the leftover bag inside to be put out again next week. The following week you put on another three bags, plus the leftover bag from last week. But again, only two bags are collected. Imagine this cycle is repeated over the following weeks.

    This is a simple description of what happens to your body when your kidneys (肾脏) don't work efficiently. Your body is not thoroughly emptied of waste products. Other areas of the body such as blood pressure and red blood cell production are affected and the insidious process that may lead to kidney failure begins.

    It's not uncommon for people to lose up to 90% of their kidney function before developing any symptoms. There may be no warning signs. This makes early detection (诊查)difficult.

    Kidney's main job is to remove toxins (毒素) and unwanted water from our blood. Every day our kidneys clean an average of 200 litres of blood. Kidney failure may be a gradual and silent process, going unnoticed because there is no obvious pain.

    Research shows that more than 35% of the patients requiring dialysis (透析) do not see a kidney specialist before they have to do so. Some risk factors for kidney disease such as age and genetic make-up are out of our control; however, some changes in lifestyle may help prevent kidney damage. Two major risk factors for kidney disease, diabetes (糖尿病) and high blood pressure, have been on the rise over the last few decades. Both conditions are chiefly affected by being overweight and not getting enough exercises, which are the potential (潜在的) risk factors for the kidney disease.