I had been following the yellowish-green markers for a “popular and easy” three-mile out-and-back hike. Immediately after the trailhead(山道的起点), the trail became very rocky and steep. But having read information about the hike, I knew within five minutes, I was supposed to reach the hike's first overlook.

    However, the overlook never arrived. Instead, I found myself lost in the woods. Pulling out my cellphone, I saw it read “no service”. I checked the last text message I'd sent to my mom. It read, “Conference ended…going for a small hike before my flight home this afternoon.” I put my phone away and kept moving and yelling, “Help! Is anybody out there?” Every so often, I'd stop to listen, but I never heard a reply.

    I got out my phone again. The battery was running out fast as it searched for a signal. I struggled to find a place where I could get service. When I did, I called my mom. It went through! In a shaky voice, I said, “Mom?” And then the call dropped. More than 1,500 miles away, my mom instantly knew something was wrong. She called the Denver Police Department and was directed to the US Forest Service.

    This was how I was introduced to John, an operator from the US Forest Service. Following John's instruction on the phone, I finally escaped from the woods. I breathed a sigh of relief. Then my phone rang, and it was John, making sure I was still going in the right direction. “By the way,” he said, “we've had your mother on hold this whole time. We know once you get down the mountain, you will absolutely want to give her a call.”

    For thousands of years, people thought of glass as something beautiful to look at. Only in large glass windows. Glass bottles and jars that hold food and drink allow us to see the contents. Glass is used to make eyeglasses, microscopes, telescopes, and many other extremely useful and necessary things.

    Until the Second World War, most of the glass used for optical (光学的) instruments was imported from Europe. However, during the war Americans could not get European glass, and they were forced to make their own. Therefore, new kinds of glass were developed that had been previously unknown. These new effects were achieved by mixing other chemical elements with the sand. Some of the new glass is very strong and can resist many kinds of shocks. Legend (传说) has it that a kind of very hard glass was invented by a Roman who showed his discovery to the Emperor. When the Emperor saw the glass he feared that it would become more valuable than gold and sliver, making his treasure worthless. Therefore, he had the glass-maker killed, and the secret was not discovered again for hundreds of years.

    In the present century, safety glass was invented for use in modem cars and planes. Safety glass is made by placing a layer of plastic between two layers of plate glass. When the outside layer of glass is broken, the pieces do not scatter (散开) and injure people. Some glass of the type is strong enough to resist bullets (子弹).

    Although nowadays plastics have replaced glass under conditions where glass might be easily broken, there are new uses being developed, for the greatest advantage of glass is that its component (组成的) parts are inexpensive and can be found all over the world.

    Diet Coke, diet Pepsi, diet pills, no-fat diet, vegetable diet… We are surrounded by the word "diet" everywhere we look and listen. We have so easily been attracted by the promise and potential of diet products that we have stopped thinking about what diet products are doing to us. We are paying for products that harm us psychologically and physically.

    Diet products significantly weaken us psychologically. On one level, we are not allowing our brain to admit that our weight problems lie not in actually losing the weight, but in controlling the consumption of fatty, high-calorie, unhealthy foods. Diet products allow us to jump over the thinking stage and go straight for the scale(秤)instead. All we have to do is to swallow or recognize the word "diet" in food labels.

    On another level, diet products have greater psychological effects. Every time we have a zero-calorie drink, we are telling ourselves without our awareness that we don't have to work to get results. Diet products make people believe that gain comes without pain, and that life can be without resistance and struggle.

    The danger of diet products lies not only in the psychological effects they have on us, but also in the physical harm that they cause. Diet foods can indirectly harm our bodies because consuming them instead of healthy foods means we are preventing our bodies from having basic nutrients. Diet foods and diet pills contain zero calorie only because the diet industry has created chemicals to produce these wonder products. Diet products may not be nutritional, and the chemicals that go into diet products are potentially dangerous.

    Now that we are aware of the effects that diet products have on us, it is time to seriously think about buying them. Losing weight lies in the power of minds, not in the power of chemicals. Once we realize this, we will be much better able to resist diet products, and therefore prevent the psychological harm that comes from using them.

    In the kitchen of my mother's houses there has always been a wooden stand (木架)with a small notepad(记事本)and a hole for a pencil.

    I'm looking for paper on which to note down the name of a book I am recommending to my mother. Over forty years since my earliest memories of the kitchen pad and pencil, five houses later, the current paper and pencil look the same as they always did. Surely it can't be the same pencil. The pad is more modern, but the wooden stand is definitely the original one.

    "I'm just amazed you still have the same stand for holding the pad and pencil after all these year." I say to her, walking back into the living-room with a sheet of paper and the pencil. "You still use a pencil. Can't you afford a pen?"

    My mother replies a little sharply. "It works perfectly well. I've always kept the stand in the kitchen. I never knew when I might want to note down an idea, and I was always in the kitchen in those days."

    Immediately I can picture her, hair wild, blue housecoat covered in flour, a wooden spoon in one hand, the pencil in the other, her mouth moving silently. My mother smiles and says, "One day I was cooking and watching baby Pauline, and I had a brilliant thought, but the stand was empty. One of the children must have taken the paper. So I just picked up the breadboard and wrote it all down on the back. It turned out to be a real breakthrough for solving the mathematical problem I was working on."

    This story—which happened before I was born—reminds me how extraordinary my mother was, and is, as a gifted mathematician. I feel embarrassed that I complain about not having enough child-free time to work. Later, when my mother is in the bathroom, I go into her kitchen and turn over the breadboards. Sure enough, on the back of the smallest one, are some penciled marks I recognize as mathematics. Those symbols have traveled unaffected through fifty years, rooted in the soil of a cheap wooden breadboard, invisible(看不到的)exhibits at every meal.

    On Sunday, November 3, 2019, most North Americans will mark the end of Daylight Saving Time (DST) by moving their clocks back an hour. This simple action will not only add an extra 60 minutes to their weekend, but also shift (变换，变动) daylight back into the morning hours, making it a little less painful to wake up for school and work during the shorter winter days.

    Operating the clocks was first suggested by Benjamin Franklin in 1784. He mentioned the idea in a letter to the editor of the Journal of Paris and advised it should be a way to save candles, but it was not taken seriously. George Hudson from New Zealand also recommended moving the clocks back two hours in 1895 to get extra daylight time to study insects. Unfortunately, neither he nor British people William Willett, who suggested it in 1907 as a way to save electricity costs, got their wish.

    It was the German Empire that began the clock shifting tradition on April 30, 1916, to save fuel needed to produce weapons and bombs for World War I. Though a few others, including the US and Britain, adopted the tradition shortly after, all the countries returned to Standard Time once the war ended, only to start DST again during World War II. Once the battle ended in 1945, the US government ended DST nationally but allowed states and districts to continue the tradition and even allowed them to establish their own start and stop dates.

    However, though there have been many attempts to persuade lawmakers to end DST, both in the US and Europe, they have not been successful. Therefore, unless you live in places like Hawaii and Arizona, you have little choice but to "Fall Back" and enjoy the extra hour this weekend! Health experts suggest the best way to adjust is going to bed at your regular time, even if the day is an hour longer.