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.”

    My friend Kathy and I were going to Colorado Springs for holiday. The only problem was, I didn't have any luggage to pack my belongings in.

    My friend Debbie offered to lend me a suitcase that belonged to her father, who had passed away long ago. “I don't know if you'll want to use it,” she said so gently, “it's very old, worn out, and such an ugly yellow color." I was so touched by her offer to lend something that belonged to her father, but I was also concerned about the possibility of it being damaged or lost. She insisted that I take it. So with the suitcase safely in hand, I boarded the train with Kathy.

    We spent two days and one night on the train, sleeping in our seats. As we slept, we were awakened at times, by the noises of the train pulling in and out of the stations.

    The next morning we eagerly awaited the announcement: Next stop, Colorado Springs. But suddenly, there came another announcement over the loud speaker. “During one of the overnight stops, many pieces of luggage were mistakenly removed from the train and left at the wrong location.”

    Kathy and I just looked at each other, as I felt the disappointment swell. Could my worst fear be coming true, was Debbie's suitcase lost?

    Just then two train conductors passed our seats. One of them jokingly said to the other, “Did you ever see such an old, ugly, brighter yellow, piece of luggage in all of your life?”

    Before the other conductor could answer, I screamed, “YES, MY SUITCASE MADE IT!”

    The two conductors stopped in their tracks! and, very red in the face, couldn't seem to apologize enough for having insulted my suitcase.

    When I returned it, I couldn't wait to get the suitcase back into Debbie's safe hands. She asked, “Did everything go well on the trip?” Somehow. I just couldn't resist telling her what had happened. She laughed heartily.

    When I recall the golden suitcase, Fm reminded, that like the suitcase, we can see ourselves as too old, useless, worn out, and of little value. Or, we can take a closer look and realize that we are one of God's most valued creations -- unique, and holding inside our most valuable possessions -- that of love, faith, hope, and wisdom.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

    A warm drink of milk before bed has long been the best choice for those wanting nights sleep. But now a study has found it really does help people nod off-if it is milked from a cow at night.

    Researchers have discovered that" night milk" contains more melatonin(褪黑激素) which has been proven to help people feel sleepy and reduce anxiety.

    The study, by researchers from Seoul, South Korea, involved mice being fed with dried milk powder made from cows milked both during the day and at night.

    Those given night milk, which contained 10 times the amount of melatonin, were less active and less anxious than those fed with the milk collected during daytime, according to the study published in The Journal of Medicinal Food.

    Night milk quickened the start of sleep and caused the mice to sleep longer.

    While the effect of cows milk harvested at different time has not been tested on humans up to now, taking melatonin drugs has been suggested to those who are struggling to fall asleep at night.

    Early studies have also showed that milk can be excellent for helping sleep because of containing Ca., which helps people to relax.

    Milk is also sugar-free and additive-free(不含添加物的) with experts advising skimmed (脱脂的) milk as the best choice before bed as it is the least fattening. The more fat you take in before bedtime, the greater burden you will put on your body at night.

    Below is a selection from a popular science book.

    If blood is red, why are veins（静脉）blue?

    Actually, veins are not blue at all. They are more of a clear, yellowish colour. Although blood looks red when it's outside the body, when it's sitting in a vein near the surface of the skin, it's more of a dark reddish purple colour. At the right depth, these blood-filled veins reflect less and light than the surrounding skin, making them look blue by comparison.

    Which works harder, your heart or your brain?

    That kind of depends on whether you are busy thinking or busy exercising. Your heart works up to three times harder during exercise, and shifts enough blood over a lifetime to fill a supertanker. But, in the long run, your brain probably tips it, because even when you're sitting still your brain is using twice as much energy as your heart, and it takes four to five times as much blood to feed it.

    Do old people shrink as they age?

    Yes and no. Many people do get shorter as they age. But, when they do, it isn't because they're shrinking all over. They simply lose height as their spine（脊柱）becomes shorter and more curved due to disuse and the effects of gravity（重力）. Many (but not all) men and women do lose height as they get older. Men lose an average of 3-4 cm in height as they age, while women may lose 5 cm or more. If you live to be 200 years old, would you keep shrinking till you were, like 60 cm tall, like a little boy again? No, because old people don't really shrink! It is not that they are growing backwards – their legs, arms and backbones getting shorter. When they do get shorter, it's because the spine has shortened a little. Or, more often, become more bait and curved.

    Why does spinning make you dizzy（眩晕的）?

    Because your brain gets confused between what you're seeing and what you're feeling. The brain senses that you're spinning using special gravity-and-motion-sensing organs in your inner ear, which work together with your eyes to keep your vision and balance stable. But when you suddenly stop spinning the system goes out of control, and your brain thinks you're moving while you're not!

    Where do feelings and emotions come from?

    Mostly from an ancient part of the brain called the limbic system. All mammals have this brain area – from mice to dogs, cats, and humans. So all mammals feel basic emotions like fear, pain and pleasure. But since human feelings also involve other. Newer bits of the brain, we feel more complex emotions than any other animal on the planet.

    If exercise wears you out, how can it be good for you?

    Because our bodies adapt to everything we do to them. And as far as your body is concerned, it's use it, or lose it”! It's not that exercise makes you healthy; it's more that a lack of exercise leaves your body weak and easily affected by disease.

    Eleven leatherback turtles (棱皮龟) are swimming across the Pacific Ocean to the Galapagos Islands in a "race". It will be reported online to attract people's attention to the situation of the endangered (濒危的) animals.

    People have put small tracking devices (跟踪装备) on the turtles so that they can monitor their journeys as they head south from their birthplace to their feeding grounds near the Galapagos, about 1,500 km away.

    People can choose a turtle online and track it at http://www.greatturtlerace.com. The turtle that travels furthest in two weeks' swimming will be the winner.

    There is no prize for the winner of the "race". Rather, they just want to help people take notice of the dangers facing the animal that has lived in the oceans for 100 million years.

    Scientists say 95 percent of the turtles in the Pacific Ocean have disappeared in the last 20 years, because of human activities like fishing, stealing their eggs and building near their homes.

    Thousands of leatherback turtles lived at Playa Grande 10 years ago, but the number has dropped below 100 in the last 5 years.

    The leatherback turtle "race" will not be broadcast on TV at the same time because the turtles leave Costa Rica at different times. Instead, a group will provide a day-to-day showing of the first 14 days of their journeys at the same time as if they were racing.

    The activity will collect money to protect Playa Grande.

    We all know cameras. But have you heard of Google's new camera? It is a small, smart device, called Clips. It comes with a case that has a clip (夹子), but it's not designed to be worn on your clothing. Most interestingly, it uses artificial intelligence to take photography out of your hands so it can capture moments on its own.

    This roughly 2-inch by 2-inch camera, with a three-hour battery life and Gorilla Glass for toughness, is intended for candid moments, like when a child does something cute that may happen too quickly for you to pull out your smart phone.

    Onboard the Clips device, it uses machine learning algorithms (计算程序) to help capture scenes. Those algorithms include face recognition. “Once it learns that there's a face you see frequently, it'll try to get nice photos of those faces,” said Juston Payne, the device's product manager. And they also want it to recognize facial expressions, which involved “training it to know what happiness looks like”. The Google team also trained it to recognize what not to shoot—like when a child's hand is over the lens, or if it is tossed in a dark purse.

    The only way to see the images is by connecting the camera with your phone, as it has no screen for viewing or editing.

    Did people think it was strange? Yes, Payne admitted. But they said they addressed that by making it obvious what it is. A green light on the front signals that the device is on. Besides, unlike a camera meant to monitor your home, it is not connected to the Internet.

    “This product is only possible because of the way that technology has advanced,” Payne said. It was only in the past year or so that they could squeeze the technology down into a device this size. Going forward, we're likely to get more assistance from the artificial intelligence packed into our apps and gadgets.