The English language has a lot of words which can be used in many different ways and in many different expressions.

    One such example is the word matter. In fact, matter can mean just about anything. It could be one of the most useful words in the English language.

    Let's get to the heart of the matter —a matter of principle(原则).

    If someone says that you owe(欠) him $50, but you don't, a friend might say, “Well, you could pay him the $50. It's not that much money. Then you won't have to hear him say it anymore. But if you do not owe him the money, do not pay him the money. It's a matter of principle.

    There is another way to use the word matter. But be careful with your choice of words.

    If you ask someone, “What's the matter?”, it shows you are worried about the other person. But saying, “What's the matter with you?” has a completely different meaning. And it usually sounds rude (粗鲁的). In fact, when you say, “What's the matter with you?” you are suggesting that the person did something wrong or stupid.

    Another expression that could sound rude is to say, “It doesn't matter to me.” Here, it depends on the context, and how you say it.

    Let's say you tell someone that a friend just got a big raise at work. That person answers with, “It doesn't matter to me.” Here, it means he or she does not care. And it sounds rude.

    But saying, “Oh, you pick where we eat dinner. It doesn't matter to me.” does not sound rude. In this situation, “it doesn't matter” shows you are easy-going(随和的).

    No matter how you look at it and what you say, matter is a very useful word. And it's only a matter of time before you will become an expert on the use of matter.

    There are many expressions with the word “dog”.

    {#blank#}1{#/blank#} They take their dogs for walks, give them goof food and medical care. However, dogs without owners to care for them lead a different kind of life. The expression, lead a dog's life, describes a person who has an unhappy existence.

    When we say we live in a dog-eat-dog world,{#blank#}2{#/blank#}A person has to work hard like a dog to be successful. Such hard work can make people dog-tired. And, the situation would be even worse if they became sick as a dog.

    Still, people say every dog has its day. This means that every person enjoys a successful period during his or her life.{#blank#}3{#/blank#} Yet, some people say that you can never teach an old dog new tricks. They believe that older people do not like to learn new skills and will not change the way they do things.

    Some people are compared to dogs in bad ways. People who are unkind or uncaring can be described as junkyard dogs living in places where people throw away things they do not want. Junkyard dogs are often used to guard this property. They bark or attack people who try to enter the property. However, sometimes a person who appears to be mean and threatening is really not so bad. {#blank#}4{#/blank#}

    Dog expressions are also used to describe the weather. The dog days of summer are the hottest days of the year. {#blank#}5{#/blank#} But we do not want it to rain cats and dogs.

A. We could say his bark is worse than his bite.

B. That means many people are competing for the same things, like good jobs.

C. But there are many difficulties on the road to success.

D. People love dogs and treat them well.

E. To be successful, people often have to learn new skills.

F. Dogs are loyal to people.

G. A rainstorm may cool the weather.

    Feeling blue about the world? “Cheer up.” says science writer Matt Ridley. “The world has never been a better place to live in, and it will keep on getting better both for humans and for nature.”

    Ridley calls himself a rational optimist—rational, because he's carefully weighed the evidence; optimistic, because that evidence shows human progress to be both unavoidable and good. And this is what he's set out to prove from a unique point of view in his most recent book, The Rational Optimist. He views mankind as a grand enterprise that, on the whole, has done little but progress for 100,000 years. He backs his findings with hard facts gathered through years of research.

    Here's how he explains his views.

    1) Shopping fuels invention

    It is reported that there are more than ten billion different products for sale in London alone. Even allowing for the many people who still live in poverty, our own generation has access to more nutritious food, more convenient transport, bigger houses, better cars, and, of course, more pounds and dollars than any who lived before us. This will continue as long as we use these things to make other things. The more we specialize and exchange, the better off we'll be.

    2)Brilliant advances

    One reason we are richer, healthier, taller, cleverer, longer­lived and freer than ever before is that the four most basic human needs—food, clothing, fuel and shelter—have grown  a lot cheaper. Take one example. In 1800 a candle providing one hour's light cost six hours' work.  In the 1880s the same light from an oil lamp took 15 minutes' work to pay for.  In 1950 it was eight seconds. Today it's half second.

    3) Let's not kill ourselves for climate change

    Mitigating (减轻) climate change could prove just as damaging to human welfare as climate change itself.  A child that dies from indoor smoke in a village, where the use of fossil­fuel (化石燃料) electricity is forbidden by well­meaning members of green political movements trying to save the world, is just as great a tragedy as a child that dies in a flood caused by climate change. If climate change proves to be mild, but cutting carbon causes real pain, we may well find that we have stopped a nose­bleed by putting a tourniquet (止血带) around our necks.

    Do you want to live another 100 years or more? Some experts say that scientific advances will one day enable humans to last tens of years beyond what is now seen as the natural limit of the human life span.

    "I think we are knocking at the door of immortality(永生)," said Michael Zey, a Montclair State University business professor and author of two books on the future. "I think by 2075 we will see it and that' s a conservative estimate(保守的估计)."

    At the conference in San Francisco, Donald Louria, a professor at New Jersey Medical School in Newark said advances in using genes as well as nanotechnology(纳米技术) make it likely that humans will live in the future beyond what has been possible in the past. "There is a great effort so that people can live from 120 to 180 years," he said. "Some have suggested that there is no limit and that people could live to 200 or 300 or 500 years."

    However, many scientists who specialize in aging are doubtful about it and say the human body is just not designed to last past about 120 years. Even with healthier lifestyles and less disease, they say failure of the brain and organs will finally lead all humans to death.

    Scientists also differ on what kind of life the super aged might live. "It remains to be seen if you pass 120, you know; could you be healthy enough to have good quality of life?" said Leonard Poon, director of the University of Georgia Gerontology Centre. "At present people who could get to that point are not in good health at all."

    Ever since mobile phones became widely used around the world, there have been concerns about how safe they are. All mobile phones give off a small amount of radiation when in use, which many believe could be a cause of cancer. However, two recently published studies tried to finally answer the question of whether using mobile phones actually brings a dangerous risk to humans.

    Carried out by the US government, the studies exposed rats and mice to radiation over the course of two years. A small number of the rats were found to have developed heart tumors (肿瘤) as a direct result of the radiation exposure. However, John Bucher, one of the study's authors, said that the animals were exposed to far more radiation than even the heaviest mobile phone user would usually be, reported The New York Times. Bucher also added that the findings didn't make him want to change his or his family's mobile phone usage habits.

    Indeed, the US Food and Drug Administration said it believes that it has “not found enough evidence that there are negative health effects on humans” from mobile phone use. Although mobile phones do give off radiation, it's a different type of radiation than that given off by dangerous sources.

    High-energy radiation – such as that given off by nuclear waste – is known to be very dangerous to humans as it is able to damage our DNA, leading to cancer or even death. On the other hand, low-energy radiation – such as the one given off by mobile phones – is considered to be harmless.

    We're exposed to this all the time, as it's given off by everyday objects like WiFi routers (路由器), televisions, and even bananas. Some argue that when it comes to human health, however, you can't be more concerned, even if the risk is only small. For those people, an earphone is advised when they are making phone calls and the time spent using mobile phones can be limited.

    But don't worry: there's no need to take bananas off the menu.

    The purpose of our entire life could be summed up into one accurate word—happiness. Satisfaction in life will always bring happiness. {#blank#}1{#/blank#}This article will share ways to stay happy and satisfied.

    Remind yourself of things that make you happy. For many of us, some of the things and people in our lives are what make us happy. {#blank#}2{#/blank#} It also could be the conversations you have with your significant friends. This makes it possible for you to look within your circle to find happiness. Reminding yourself that you have beautiful people in your life will keep you fulfilled when you're experiencing depression(抑郁).

    Keep your focus on your life goals.{#blank#}3{#/blank#} Realizing that you can achieve your goals and make your dreams come true will help you stay fulfilled. Experts recommend celebrating every little win on your way to success. So take time and celebrate the small steps you've successfully completed.

    Only spend time with people that make you happy. {#blank#}4{#/blank#} This means you have to cut off communications with those that constantly let you down by injecting negative emotions(情绪) into your life.

    {#blank#}5{#/blank#} Do you often find that you criticize yourself too much? We're humans and that means we will make a couple of mistakes every now and then. Look at the fun side of it and make fun of yourself.

A. But how do you get the feeling?

B. Stop taking yourself too seriously.

C. Go out of your way to make others happy.

D. It's true that you can't make everybody happy.

E. It could be the smile on the face of a loved one.

F. People often get depressed when they stop focusing on their main goals.

G. The people you surround yourselves with can affect your emotions greatly.