What will power your house in the future？Nuclear, wind, or solar power？According toscientists at the Massachusetts Institute of Technology(MIT)in the US, it might beleaves—but artificial(人造的)ones.

    Natural leaves are able to change sunlight and water intoenergy. It is known as photosynthesis(光合作用). Nowresearchers have found a way to imitate this seemingly simple process.

    The artificial leaf developed by Daniel Nocera and hiscolleagues at MIT can be seen as a special silicon chip with catalysts(催化剂). Similar tonatural leaves, it can splitwater into hydrogen and oxygen when put into a bucket of water. The hydrogenand oxygen gases are then stored in a fuel cell, which usesthose two materials to produce electricity, located eitheron top of a house or beside the house.

Though the leaf is only about the shape of a poker card, scientistsclaimed that it is promising to be an inexpensive source of electricity indeveloping countries.“ One can imagine villages in India and Africa not longfrom now purchasing an affordable basic power system based on this technology, ”said Noceraat a conference of the American Chemical Society.

    The artificial leaf is not a new idea. The first artificial leafwas invented in 1997 but was too expensive and unstable for practical use. Thenew leaf, by contrast, is made ofcheap materials, easy to useand highly stable. In laboratory studies, Nocera showedthat an artificial leaf prototype(原型)could operatecontinuously for at least 45 hours without a drop in activity.

    The wonderful improvements come from Nocera's recent discoveryof several powerful, new andinexpensive catalysts. These catalysts make the energy transformation insidethe leaf more efficient with water and sunlight. Right now, the new leafis about 10 times more efficient at carrying out photosynthesis than a naturalone. Besides, the device canrun in whatever water is available；that is, it doesn'tneed pure water. This is important for some countries that don't have access topure water.

    With the goal to “make each home its own power station” and“give energy to the poor”, scientistsbelieve that the new technology could be widely used in developing countries, especially inIndia and rural China.

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    Being outspoken is a quality that, when used with skill and wisdom, can set you apart from the crowd. {#blank#}1{#/blank#} The quality of being outspoken is a positive and active skill. Here are some tips.

    Gain self-knowledge(自找认识)through journaling. Knowing who you are, what you believe, and how you feel is the beginning of knowing yourself, and journaling is a great way to gain that knowledge. {#blank#}2{#/blank#} Not only can you know yourself better, journaling is an excellent tool to improve self-confidence. Self-confidence is the foundation of being outspoken.

    {#blank#}3{#/blank#} In order to be outspoken, you have to believe that your voice has worth. You have to believe that your input will make any conversation better. And it probably will! It's different opinions that make conversations or debates interesting.

    Overcome shyness. The fact that you're confident doesn't mean you like hearing your own voice. {#blank#}4{#/blank#} Overcoming a natural tendency towards shyness can seem horrible, but doing the opposite of your natural instinct can open up a whole new set of choices: brave choices.

    Back up your opinion with facts. Some people feel uncomfortable having or expressing an opinion because they don't know much about a topic. {#blank#}5{#/blank#} 

A. Be confident

B. Open your mind and speak it out.

C. The next step is overcoming your shyness.

D. Practice journaling for 15 minutes each night before bed.

E. Being outspoken is to speak your mind—to be honest and frank.

F. Allowing the other parties to make their points fully can help you seem more reasonable.

G. You can combat this feeling and have more confidence about your opinion if you learn facts that can support your opinion.

    Nuclear power's danger to health, safety, and even life itself can be summed up in one word: radiation.

    Nuclear radiation has a certain mystery about it, partly because it cannot be detected by human senses. It can't be seen or heard, or touched or tasted, even though it may be all around us. There are other things like that. For example, radio waves are all around us but we can't detect them, sense them, without a radio receiver. Similarly, we can't sense radioactivity without a radiation detector. But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.

    At very high levels, radiation can kill an animal or human being immediately by killing masses of cells in vital organs. But even the lowest levels can do serious damage. There is no levels of radiation that is completely safe. If the radiation does not hit anything important, the damage may not be serious. This is the case when only a few cells are hit, and if they are killed immediately. Your body will replace the dead cells with healthy ones. But if the few cells are only damaged, and if they reproduce themselves, you may be in trouble. They can grow into cancer. Sometimes this does not show up for many years.

    This is another reason for some of the mystery about nuclear radiation. Serious damage can be done without the victim being aware at the time that damage has occurred. A person can be irradiated(辐射)and feel fine, then die for cancer five, ten, or twenty years later as a result. Or a child can be born weak as a result of radiation absorbed by its grandparents.

    Radiation can hurt us. We must know the truth.

    There are many dangerous sea creatures in the world. The following are some examples.

    The needlefish are commonly seen living near the surface of tropical (热带的) waters. But they can also break cover the water，and once in the air they can become dangerous flying swords. Though it is rare，people have been seriously hurt and even killed by the fish．Night fishermen in small boats are at particular risk because their lights may attract the fish.

    Saltwater crocodiles are the world's largest crocodiles，sometimes reaching 23 feet in length and topping 2，200 pounds. Yet these crocodiles hunt quietly，lying in wait below shoreline waters to attack turtles and thirsty animals that have come to drink. Saltwater crocodiles kill a number of people each year.

    There is no doubt that the great white shark sits atop the ocean food chain. The world's largest fish can weigh at over 5，000 pounds and reach lengths of more than 20 feet. Great white sharks have about 3，000 teeth，which they typically sink into sea lions，seals，and sea turtles. These sharks are responsible for a third to a half of the 100 shark attacks on humans every year.

    The sea anemone (海葵) may look like the beautiful flower for which it's named，but fish that swim too close may regret it. The sea anemone，which lives on the sea floor，uses its poisonous tentacles (触须) to stab passing creatures with a kind of poison—making them helpless and fit to be eaten.

    The surgeonfish (刺尾鱼) is an attractive reef fish that is poisonous. Scientists believe that the world's seas hold some 1, 200 different surgeonfish species and think that they injure about

    50，000 people per year. But the surgeonfish poison can also bring great benefit—they are useful in the development of new drugs.

Once a blind man fell flat on his face, which was awful but finally harmless. His service dog, however, was trained lo tum to an adult if the owner had an epileptic seizure (癫瘤发作). While the dog did what it was taught, the first person it found was merely annoyed but not alarmed. Thankfully, the dog's owner was not in the situation of medical emergency. But the experience inspired him to share this information on social media, "If a service dog without a person approaches you, it means the person is down and in need of help," the owner explained. "Don't get scared, don't get annoyed, and follow the dog! If the first person doesn't cooperate, it moves on.

Referring to the accident, a TV presenter asked a dog trainer, Olivia, some basic questions about service dogs, including how humans should react if an unaccompanied service dog approaches them.

"What they're going to do is sniff and gently push your leg," the trainer explained, specifically noting that service dogs are not usually trained to jump or bark. "If you see a dog in a vest without a person around it, follow it." When asked if one should say something to indicate they're prepared to follow the dog, Olivia said," there's no clear command. Just start walking wherever the dog leads."

Olivia concluded the TV show by adding that those who rely on service dogs could train their companions to move along to someone else, if the first person the dog came upon reacted negatively to its request. Doing so could finally save the owner's life.