Most people know precious gemstones (宝石) by their appearances. An emerald flashes deep green, a ruby seems to hold a red fire inside, and a diamond shines like a star. It's more difficult to tell where the gem was mined, since a diamond from Australia or Arkansas may appear the same to one from the Democratic Republic of the Congo. However, recently, a team of scientists has found a way to identify a gemstone's origin.

    Beneath the surface of a gemstone, on the tiny level of atoms and molecules（分子）, lie clues (线索) to its origin. At this year's meeting of the Geological Society of America in Minneapolis, Catherine McManus reported on a technique that uses lasers (激光) to clarify these clues and identify a stone's homeland. McManus directs scientific research at Materialytics, in Killeen, Texas. The company is developing the technique. “With enough data, we could identify which country, which mining place, even the individual mine a gemstone comes from,” McManus told Science News.

    Some gemstones, including many diamonds, come from war-torn countries. Sales of those “blood minerals” may encourage violent civil wars where innocent people are injured or killed. In an effort to reduce the trade in blood minerals, the U.S. government passed law in July 2010 that requires companies that sell gemstones to determine the origins of their stones.

    To figure out where gemstones come from, McManus and her team focus a powerful laser on a small sample of the gemstone. The technique is called laser-induced breakdown spectroscopy. Just as heat can turn ice into water or water into steam, energy from the laser changes the state of matter of the stone. The laser changes a miniscule part of the gemstone into plasma, a gas state of matter in which tiny particles（微粒）called electrons separate from atoms.

    The plasma, which is superhot, produces a light pattern. (The science of analyzing this kind of light pattern is called spectroscopy.) Different elements produce different patterns, but McManus and her team say that gemstones from the same area produce similar patterns. Materialytics has already collected patterns from thousands of gemstones, including more than 200 from diamonds. They can compare the light pattern from an unknown gemstone to patterns they do know and look for a match. The light pattern acts like a signature, telling the researchers the origin of the gemstone.

    In a small test, the laser technique correctly identified the origins of 95 out of every 100 diamonds. For gemstones like emeralds and rubies, the technique proved successful for 98 out of every 100 stones. The scientists need to collect and analyze more samples, including those from war-torn countries, before the tool is ready for commercial use.

    Scientists like Barbara Dutrow, a mineralogist from Louisiana State University in Baton Rouge, find the technique exciting. “This is a basic new tool that could provide a better fingerprint of a material from a particular locality,” she told Science News.

    Glacier Bay is one of the most famous parks in America, located in the state of Alaska. This park in the southeastern part of the state covers more than 1 million hectares of Alaskan wilderness. It includes mountains, glaciers (冰川), bays, and even rainforests. Glacier Bay supports hundreds of kinds of animals, including many species of birds, fish, bears, whales and sea lions.

    As its name suggests, much of Glacier Bay National Park is covered by glaciers. A glacier is a large area of ice that moves slowly down a slope (斜坡) or valley, or over a wide area of land. Glaciers cover more than 5,000 square kilometers of the park.

    Glacial ice has shaped the land over the last seven million years. The glaciers found in the park today are what remains from an ice advance known as the Little Ice Age. That period began about 4,000 years ago.

    During the Little Ice Age, the cold weather caused the ice to grow and advance. That situation continued until about 1,700s, when the climate began to warm. The higher temperatures caused the ice to start melting. That melting led the huge glacier to separate into more than 1,000 different glaciers.

    The extremely tall and jagged (参差不齐的) mountains seen in Glacier Bay National Park were formed by the ice advancing and then melting over time. The melting of the ice also created water that filled in and created the many fjords (峡湾) within the park. Fjords are narrow parts of the ocean that sit between cliffs or mountains.

    The huge amount of water from the melted ice killed off many kinds of plants. Vegetation returned to the area over the next 200 years. The regrowth in plants also brought back many animals to the land. This return of life to Glacier Bay is why it is sometimes called “a land reborn” by people.

    Teenagers who spend hours in front of the television may have a poorer diet as young adults.

    A study, which included nearly 1,400 high school students, found those who watched TV for five hours or more per day had less healthy diets than peers(同龄人) five years later. Why does this happen? Should the parents take any measures?

    On the one hand, people who spend a lot of time in front of the TV, especially teenagers, may snack more, and that may affect their long-term diet quality.

    On the other hand, TV ads for fast food, sweets and snacks tempt teenagers to eat more of those foods. And TV time might also replace exercise time for some kids.

    Lead researcher Dr. Daheia J. Barr-Anderson, of the University of Minnesota in Minneapolis, told Reuters Health a clear correlation between TV time during high school and diet quality in young adulthood. While the heaviest TV viewers were eating the most junk food, those who'd watched less than two hours per day had the highest intake(吸收) of fruits, vegetables, whole grains and high-calcium food. In her opinion, parents should limit and monitor TV viewing.

    As far as I am concerned, children should watch no more than two hours of television per day. And parents should set a good example by eating right, being physically active and curbing their own TV time.

    Listening to others requires entering actively and imaginatively into the situation and trying to understand a frame of reference different from your own, and yet so many of us don't listen properly as we should. Listening means more than just sitting silently while someone else talks.{#blank#}1{#/blank#}

    Here are some ways to become a better listener.

    {#blank#}2{#/blank#} Make sure you actually hear fully what your friend is saying, and you can't cut your friend off verbally carelessly. While you might intend to help move the conversation along your friend might feel as if what he has said needs to be continually talked over or sounds anything but interesting.

    Nod to encourage the conversation along. A better option to let your friend know you're interested in what he says is just to nod along from time to time. Sometimes you nod along but then start thinking about something unrelated to what he could say.{#blank#}3{#/blank#}

    Turn out background noise. If you're easily distracted by laughter, glasses clinking, children crying, you might need to work extra hard to focus only on your friend.{#blank#}4{#/blank#} Don't hesitate to tell them that the background noises are getting in the way. If you can't focus, try moving to another area.

    Don't text or look at your phone!{#blank#}5{#/blank#} For you see, when you're sitting in front of someone, he is the most important person in your world at that moment.

A. Stop the speaker whenever you have a question.

B. Practice silence when someone else is talking.

C. If necessary, ask your friend to repeat himself.

D. Whoever is calling or texting can wait until you're done with your conversation.

E. It means trying to see the problem the way the speaker sees it.

F. In this case, try to push away your thoughts until you're absorbed in what your friend is saying.

G Remembering ideas from previous conversations proves that your attention is kept and encourages your friend to continue.

    In life, everyone wants to have friends who he or she can trust forever. {#blank#}1{#/blank#} It is scary because in most cases you have to get out of your comfort zone and put yourself out there.

    However, once the strangeness becomes a thought of the past, it becomes much easier to talk to potential new friends. {#blank#}2{#/blank#}Get over the shyness of meeting new people and be yourself. Start out with a simple conversation like "Hello, I like your coat" or a discussion about the weather. Those icebreakers will give you the time to feel comfortable and help you open the floor for future conversations.

    {#blank#}3{#/blank#}It can be attending a book club or maybe just enjoying a cup of coffee. Making new friendships means learning about someone and sharing stories about each other's life. Think of your new friendship as a plant. In order to grow, you have to water it and provide it with sunlight. {#blank#}4{#/blank#} If you want to make new friends, you have to be willing to make the effort. Keep in mind that some people are more outing than others and it's okay to be reserved(矜持). But it's necessary to make use of opportunities to develop your newly-found friendship.

    One thing to be cautious about, when you meet new people, is to be always genuine(真诚的).{#blank#}5{#/blank#}If you don't like fishing or running, then don't pretend that you do just so someone will be friends with you. Find people that share common interests and goals and build your friendship. Then you'll find it's much easier to keep friendships.

A. Friendships are quite similar.

B. Friendships are great support systems.

C. In most cases, you are your biggest road block.

D. Be true to yourself and don't be someone that you are not.

E. However, making new friends is much easier said than done.

F. Building new friendships means spending quality time together.

G. Then find a common ground and build your friendship around that.

Best Way to Lose Weight – Dieting Tips

    How do you eat right to lose weight fast? You'll discover there are a great number of weight loss diets which promise to help you drop the pounds fast.{#blank#}1{#/blank#}

    Many weight loss diets are aimed at losing weight fast, but aren't necessarily healthy and won't create a long-term change for the better. {#blank#}2{#/blank#} That means you'll choose a diet which doesn't cut out any necessary nutrients(营养物). Most diets suggest that you stop eating fat or carbs(含碳水化合物的食物).{#blank#}3{#/blank#} You'll need to make clear of your own body type before making a diet plan. You might also need to try different ways before finding the best way.

    If you just need to shake a few pounds off, your plan won't be the same as one to lose weight in the long term. The best short-term weight loss plan will be stronger than the best long-term weight loss plan, but it shouldn't get rid of necessary nutrition. {#blank#}4{#/blank#}Your body will go into "starvation mode" and your metabolism(新陈代谢) will slow down. As a result your body will keep more weight.

    {#blank#}5{#/blank#} Spread out your meals evenly throughout the day. Any larger meals should be eaten earlier in the day. That gives your body more time and opportunity to burn calories. If you eat a lot before bed, those calories won't burn but become fat.

A. In fact many people feel it hard to lose weight.

B. Once you start your plan, you shouldn't stop.

C. But do they really work?

D. If you try to make yourself feel hungry, you won't achieve long-term results.

E. The best way to lose weight should be useful in the long term.

F. While this may help some people, there is no plan that is perfect for all.

G. Besides improving your metabolism, you also should pay attention to when you eat.