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.”

    Gold Coast family holidays are always great fun whether you are from Australia or from abroad. There are beautiful beaches, adventure parks, nature parks and so much more.

    There are so many sights to see here. It is a pity to drive in a car and you'll miss a great part of it. Australia is home to many animals and birds that can only be seen when moving slowly and going into the areas that they live.

    When you are on a bicycle, you have the advantage of being able to stop whenever you want to see an interesting animal or bird that you have never seen before. It is a quieter mode (方式) of transportation as well, so you might even be able to take a picture. When you are on the beach, you can breathe that clean air and view the beauty of the water and sand. It is a totally different experience from either simply sunbathing or passing it in a car.

    There are many choices of hiring a bicycle to experience the Gold Coast attractions. There are stores that will fit a bike perfectly to your size. These bikes for both adults and children are in many styles and colors to please any taste. If you have ever wanted to try a tandem bike (双人单车), now is your chance, because they have those too.

    A bicycle hire on Gold Coast is something that everyone should try at least once. This is a wonderful chance for anyone who likes to cycle and it is also a cheap way to travel with your family.

    Like many other of our lives today, education has become a global enterprise. In microcosm（微观世界）, my school is proof of how global. Monkseaton High School is an ordinary state-funded school of 850 students in the unfashionable part of northeastern England. Over the past seven years it has sent 12 students to American universities — two of them to Harvard. Monkseaton has, in turn, attracted students from other countries, including Germany and Latvia. Monkseaton now almost routinely receives inquiries from students in Eastern European countries. Obviously, learning English is a big draw, but his pattern ofstudent movement was unheard of five years ago.

    The brain drain is a universal phenomenon, and countries that don't face up to the new reality will be losing some of their most precious resources. The northeast of England is its poorest region, and has experienced a severe loss of highly qualified professionals-to-be. Some of the most able 18-year-olds are going to other parts of Britain, even to other countries. What is happening here is happening to Britain as a whole. Most noticeably, there is a growing trend of British students taking degrees in American universities. This year the number will break the psychological barrier of 1,000 students for the first time.

    And what is happening at the secondary-school level is happening to higher education. Wherever they come from, today's students have a very different perspective on education from their parents. Because of television, the Internet and their travels, these students see the world as a much smaller place than their parents once did. They are more confident in accepting the challenge of moving from one country to another, from one culture to another; in many cases they can even apply to schools over the Internet. Students are also more aware of the overall cost of education and are looking for value for money. Plus, for many, education linked to travel is a better option than education at home.

    In a world with limited land, water and other natural resources (资源), the harm from the traditional business model is on the rise. Actually, the past decades has seen more and more forests disappearing and globe becoming increasingly warm. People now realize that this unhealthy situation must be changed, and that we must be able to develop in sustainable (可持续的) ways. That means growth with low carbon or development of sustainable products. In other words, we should keep the earth healthy while using its supply of natural resources.

    Today, sustainable development is a proper trend in many countries. According to a recent study, the global market for low-carbon energy will become three times bigger over the next decades. China, for example, has set its mind on leading that market, hoping to seize chances in the new round of the global energy revolution. It is now trying hard to make full use of wind and solar energy, and is spending a huge amount of money making electric cars and high-speed trains. In addition, we are also seeing great growth in the global markets for sustainable products such as palm oil (棕榈油), which is produced without cutting down valuable rainforest. In recent years the markets for sustainable products have grown by more than 50%.

    The major challenge of this century is to find ways to meet the needs of growing population within the limits of this single planet. That is no small task, but it offers abundant new chances for sustainable product industries.

Yawning（哈欠）sends out certain messages—either “Oh, this movie is boring" or "I probably need to get some sleep". But did you know that a yawn can also help your brain to cool down when it is so overheated?

    A new study, led by a research team of Princeton University, has indicated（表明）that yawning could be the brain's natural way of regulating temperature. People yawn more often when the temperature outdoors is lower than their body temperature but are less likely to yawn when it is hotter outdoors, according to Sciencedaily.com.

    The research team did an experiment on 160 people, 80 in summer and 80 in winter, to examine how often they yawned at different air temperatures. The study found that people yawned more often in winter than in summer. Scientists say that when the air temperature is lower outside the body, there is heat exchange between the overheated brain and the cool air. But when the air temperature is higher than or equal to the body, people are less likely to yawn because the hot air they breathe in will make the brain even hotter.

    When people yawn, their jaw is also stretched, which increases blood flow and may also help cool the brain.

    The study showed that the amount someone yawned could be related to the amount of time they spent outside. The longer they spent outside in summer, the less they yawn. Nearly 40 percent of participants yawned within their first five minutes outside, but after that the percentage was reduced to less than 10 percent.

    However, the result was the opposite in winter. The number of people who yawned increased when they spent more than five minutes outdoors. But the change was only slight compared to summertime.

    According to Gallup, this is the first report to show that yawning frequencies(频率) change depending on season. This could help us to understand better the way our brains work. It may also help us understand the reason why frequent yawning can sometimes be a sign of brain disease.

    Nola (August 21, 1974-November 22, 2015)was a northern white rhino(犀牛) who lived at the San Diego Zoo Safari Park near Escondido, California. At her death, she was one of only four remaining northern white rhinos in the world. The other three lived in Kenya. World Rhino Day, held on September 2, is to raise awareness(意识) of the less than 30, 000 other rhinos left on Earth.

    "Rhinos need our help today, not tomorrow," Nola's lead keeper Jane Kennedy said. "Last year we lost over 1, 200 rhinos just in South Africa. If we continue to lose more than 1, 000 rhinos a year, in 10 to 20years all the rhinos on the planet will be gone. "

    "Unfortunately, most animals are in danger of dying out because of humans," Kennedy says. "Humans have either poached animals, or because there are over seven billion of us, we've taken up too much of the world's resources". Poachers illegally hunt rhinos for their horns. They sell the horns for thousands of dollars per pound, to be used for art, jewelry, and decorations. Experts believe that one rhino is poached every eight hours.

    In 1975, the San Diego Zoo Institute for Conservation Research started the Frozen Zoo, a program through which researchers have collected cell (细胞) samples from more than 8, 000 different types of animals, including the northern white rhino. Scientists hope that by studying the rhino cells, they will get greater understanding of it, and will find ways to increase its numbers.

    Jane Kennedy describes World Rhino Day as "a celebration of rhinos along with an awareness campaign(活动)for everybody across the world to know that rhinos need our help. "At the San Diego Zoo, children and adults are welcome to visit and speak with zookeepers to learn about rhinos. But you don't have to live in San Diego to celebrate World Rhino Day. It is observed around the world, with zoos and wildlife parks holding special events and programs to teach people about rhinos, and enable them to see the animals up close. For more information, go to www. worldrhinoday.org.