We do not know when man first began to use salt, but we do know that it has been used in many different ways throughout history. Historical evidence shows, for example, that people who lived over 3,000 years ago ate salted fish. Thousands of years ago in Egypt, salt was used to preserve (保存) the dead.

    Stealing salt was considered a major crime (罪行) during some periods of history. In the eighteenth century, for example, if a person was caught stealing salt, he could be put in prison and his ears could be cut off.

    In the Roman Empire, one of the most important roads was the one that carried salt from the salt mines to Rome. Guards were stationed(安置) along the route to protect against salt thieves, and they received their pay in salt, thus bringing the English word, salary. Any guard who fell asleep while on duty was thought to be “not worth his salt”, and as a result he would get a little less salt on his next payday. The expression, “not worth his salt”, is still used today in English.

    In the modern world salt has many uses beyond the dining table. It is used in making glass and airplane parts, in the growing of crops, and in the killing of weeds (杂草). It is also used to make water soft, to melt (融化) ice on roads and highways, to make soap, and to fix colors in cloth.

    Salt can be got in various ways besides being taken from mines underground. Salt water from the ocean, salt water lakes or small seas can be used to make salt. Yet, no matter where it comes from, salt will continue to play an important role in the lives of people everywhere.

    Why should mankind explore space? Why should money, time and effort be spent exploring and researching something with so few apparent benefits? Why should resources be spent on space rather than on conditions and people on Earth? These are questions that, understandably, are very often asked.

    Perhaps the best answer lies in our genetic makeup as human beings. What drove our ancestors to move from the trees into the plains, and on into all possible areas and environments? The wider the spread of a species, the better its chance of survival. Perhaps the best reason for exploring space is this genetic tendency to expand wherever possible.

    Nearly every successful civilization has explored, because by doing so, any dangers in surrounding areas can be identified and prepared for. Without knowledge, we may be completely destroyed by the danger. With knowledge, we can lessen its effects.

    Exploration also allows minerals and other potential resources to be found. Even if we have no immediate need of them, they will perhaps be useful later. Resources may be more than physical possessions. Knowledge or techniques have been acquired through exploration. The techniques may have medical applications which can improve the length or quality of our lives. We have already benefited from other spin-offs including improvements in earthquake prediction, in satellites for weather forecasting and in communications systems. Even non-stick pans and mirrored sunglasses are by products(副产品) of technological developments in the space industry!

    While many resources are spent on what seems a small return, the exploration of space allows creative, brave and intelligent members of our species to focus on what may serve to save us. While space may hold many wonders and explanations of how the universe was formed or how it works, it also holds dangers. The danger exists, but knowledge can help human beings to survive. Without the ability to reach out across space, the chance to save ourselves might not exist.

    While Earth is the only planet known to support life, surely the adaptive ability of humans would allow us to live on other planets. It is true that the lifestyle would be different, but human life and cultures have adapted in the past and surely could in the future.

    Everyone is welcome to visit our city Los Angeles (LA). I am sure you can do many things in Los Angeles with your kids.

    Fun at the Beach

    Thanks to its almost perfect weather all through the year, a visit to the beach is one of the best things to do when in Los Angeles with your kids. While they enjoy themselves nearby, you can simply lie back and have a good rest in the sun.

    Trip to Disneyland

    A trip to the City of Angels with your little angels is incomplete (不完整的) without a visit to the Magic Kingdom. The joy they'll feel from being around all those Disney characters that they know and love will light up your day, too.

    Visit to the Museum

    If you want to turn your stay in LA into an educational one for your kids, you should visit the museum. Starting with the Natural History Museum of Los Angeles County to the California Science Center, or even the Kidspace Children's Museum in Pasadena, you have many choices. I'm sure a visit to all these places will make your kids smarter.

    Visit to the University Studios Hollywood

    Your kids could get to see interesting things from some of the most popular movies ever. From the theme park of Jurassic Park to Wisteria Lane from the TV play Desperate Housewives, the Universal Studios Hollywood is a place that we all find wonderful.

    Blue Planet II's latest episode focuses on how plastic is having a disastrous effect on the ocean and slowly poisoning our sea creatures. Researchers recently also found that sea creatures living in the deepest place on Earth, the Mariana Trench, have plastic in their stomachs. Indeed, the oceans are drowning in plastic.

    Though it seems now that the world couldn't possibly function without plastics, consumer plastics are a remarkably recent invention. The first plastic bags were introduced in the 1950s; the same decade that plastic packaging began gaining in popularity in the United States. This growth has happened so fast that science is still catching up with the change. Plastics pollution research, for instance, is still a very early science.

    We put all these plastics into the environment and we still don't really know what the outcomes are going to be. What we do know, though, is disturbing. Ocean plastic is estimated to kill millions of marine animals every year. Nearly 700 species, including endangered ones, are known to have been affected by it. One in three leatherback turtles, which often mistake plastic bags for jellyfish, have been found with plastic in their bellies. Ninety percent of seabirds are now eating plastics on a regular basis. By 2050, that figure is expected to rise to 100 percent.

    And it's not just wildlife that is threatened by the plastics in our seas. Humans are consuming plastics through the seafood we eat. I could understand why some people see ocean plastic as a disaster, worth mentioning to the same degree as climate change. But ocean plastic is not as complicated as climate change. There are no ocean trash deniers (否认者), at least so far. To do something about it, we don't have to remake our planet energy system.

This is not a problem where we don't know what the solution is. We know how to pick up garbage. Anyone can do it. We know how to dispose (处理) of it. We know how to recycle. We can all start by thinking twice before we use single-use plastic products. Things that may seem ordinary, like using a reusable bottle or a reusable bag—when taken collectively, these choices really do make a difference.

    I was on my way home from work, cutting through the Bryant Park. On that day, the sun seemed to set faster than usual, and suddenly I found myself walking in the dark. I was less than half a mile from my apartment, but the path would lead me over a bridge, across train tracks, and through an unlit underpass.

    Then I heard him – a stranger running alongside me, partly obscured(遮掩) by the bushes. My mouth went dry; my legs felt like water. But I didn't pick up my pace – instead, I stopped, turned, and faced him. He came out of the bushes and said he'd been watching me "for a long time".

    As he walked beside me, I guided us towards the edge of the park. When we reached the bridge, a train rumbled(轰鸣着缓慢行进) past, and he seized the moment, attacking me with a knife around my throat. The self-defense skills I had learned years before kicked in, and I pushed my finger into his eye, hard. And then came the shock: That didn't frighten him away. My mind flashed back to a tip from an old guitar teacher: "Press the strings like you're squeezing a flea(跳蚤)." I put all my strength into that finger, and finally he let go.

    I was shaking with fear, but I looked him straight in the eye and began to back away. I turned to run the hell out of there, but then I remembered another self-defense lesson: Never run, because then you're a target. So I walked away alone – through the dark tunnel as I dialed 911 with trembling fingers. If you ever find yourself in this situation, use these self-defense skills that you already know. They can really make all the difference to you.

Understanding the link between the clean environment and human life is not a new concept. In fact, it was noticed as early as ancient Roman times. Today we see how green living has influenced our everyday lives. There is a growing community of people who embrace a zero waste lifestyle and make changes to the way they live to reduce their carbon footprint. 

Living a zero waste lifestyle means doing one's best to achieve the aim of not sending anything to a landfill. People who adopt this lifestyle ultimately cut down on their waste by reducing what they need and want. They reuse what they own, sending few things to be recycled. 

Many people who adopt the zero waste lifestyle claim to be frustrated by the many harmful chemical substances found in beauty and cleaning products. They also find the uses of disposable items and excessive packaging the same. For example, how many times have we had to peel away layers of plastic wrap and cardboard before finally taking out the item which we had bought? Instead of buying prepackaged food and goods, those who identify with the zero waste philosophy tend to shop in stores that allow them to make purchases and bring their own cloth bags and glass jars to store their purchases. 

Many people have the misconception that it is easier to live a zero waste lifestyle in the West. Nevertheless, Malaysian environmental journalist, Ms Aurora Tin, has proven that a zero waste lifestyle is possible even in the Asian context. Instead of going to the supermarket to buy prepackaged foods, Ms Tin now visits the wet market and brings her own bags for vegetables. She has even stopped using store-bought toothpaste and make her own toothpaste from coconut oil and baking soda. This lifestyle may be too big a change for the average person, but we could follow her suit to make gradual changes to our own lives.