Boys and girls,as we all know,most people,especially young people ,tend to care about their hair much because hair plays a very important role in our appearance.But can you imagine what other uses hair has?Do you have any idea that human hair may become a new solar energy soutce?Before we begin with the new content of our Physics ,let me tell you a new invention first. It's reported that a Nepali teenager has designed a $32 solar panel using human hair. Milan Karki,who is 18 years old and lives in a village in rural Nepal,used human hair to replace silicon ,which is a common but expensive componet of solar panels. By using hair as a replacement,Karki says that solar panels can be produced for around $32,a price that could be halved if they were mass-produced. The solar panel works,because melanin ,which gives hair its colour,is light sensitive and can act as an elecrtical conductor.Kaiki was inspired to think of the idea by a Stephen Hawking book ,which explained how to create elecrtic energy from hair. The device that Karki has invented is capable of producing 9V or 18V of energy--plenty to charge a mobile phone. "Half a kilo of hair can be bought for only 16p in Nepal and lasts a few months;whereas a pack of batteries would cost50p and lasts few nights,"according to The Daily Mail. The solar panel is claimed to be easy to service as the hair is easy to replace. Karki has now seng out several devices to other disrticts near his home for tetimg .He said,"First I wanted to provide elecricity for my home,then my village .Now I am thinking for the whole worle." So next time when you have a haircut,do remember to keep your hair cut down to use for energy.Perhaps you can also provide elecrticity for your home,even your village using your own hair. Who do you suppose the speaker is ? A) A famous scientist. B) A reporter of The Daily Mail. C) A senior hight school teacher. D) A famous hairdresser.
C
With fuel costs rising and airlines finding more fees to impose on travelers every day, airfare isn't getting any cheaper. Since you can't drive to all your dream destinations, flying is the only way to go sometimes and, undeniably, the fastest. Luckily, there are plenty of ways to find the most affordable fares and also avoid paying as many extra charges as possible when you plan ahead. Getting the best fare. Airlines put out their fare sales on Tuesday morning, making this day the best day to book a flight for less. Fly during the least popular times. Tuesday, Wednesday and Saturday are the slowest days to fly, which means cheaper deals than the rest of the week. You can also find reduced rates on early morning flights, since many people don't like to get up before the sun to get to the airport. Earlier boarding times can also considerably cut down your chances of getting bumped on an overbooked flight or delayed because of other delayed flights or mechanical issues. Choose your seat later. Some airlines charge you to pick your seat when you book online, adding even more to the bottom line of your ticket cost. If you show up early on your travel day, you can still get suitable seats. Some of the best seats get held back until flight day, unless others are willing to pay extra for them ahead of time, so you still have the chance at one of those. Fly on holidays. You already know that summer is the most expensive time to fly, and even though most other times are more affordable, the days surrounding holidays can be crazy. Save big if you're willing to travel on major holidays, such as Thanksgiving and Christmas. Don't wait until the last-minute to book. Many travelers don't know that there's a sweet spot for booking and getting the best price on your tickets. Book too early or too late and you could end up paying more than you need to. The best time to book is between three months and six weeks from when you want to travel. Avoiding extra fees Airlines will charge for just about anything these days. Some have... Which of the following will help to cost you less for a flight? A) Book your flight on Thursday. B) Travel surrounding Christmas. C) Pick your seat the moment you book online. D) Book early morning flights.
D
Q: Scientists from the Max Plank Institute for Biological Cybernetics in Tubingen, Germany, have presented the first experimental evidence that people do end up walking in circles if lost in unfamiliar areas.The study, published in the journal Current Biology, examined the tracks of people who walked for several hours in the Sahara desert in Tunisia and in the Bienwald forest in Germany.Researchers Jan Souman and Marc Ernst said the scientists used the global positioning system (GPS) to record these paths.The results showed that the walkers were only able to keep a straight line when the sun or moon was visible.As soon as the sun disappeared behind some clouds, people started to walk in circles without even noticing it. Souman said one explanation offered in the past for people walking in circles was that most people have one leg longer or stronger than the other, which would produce a systematic bias in one direction.To test .the researchers asked people to walk straight while blindfolded which removed the effects of vision.They found that these circles were rarely in a systematic direction, with the same person sometimes switching to the left and sometimes to the right. "Most of the participants in the study walked in circles, sometimes in extremely small ones.Walking in circles is therefore not caused by differences in leg length or strength, but more likely the result of increasing uncertainty about where straight ahead is," said Souman, "Small random errors in the various sensory signals that provide information about walking direction add up over time, making what a person perceives to be straight ahead drift away from the true straight ahead direction." Which of the following statements is true? A) People walk straight in the day. B) The farther people walk, the greater the direction bias grows. C) People walk only in large circles. D) Researchers use the global positioning system to record their tracks.
A: B
(Question)
Happiness is important for everyone. Most people want to be happy but few know how to find happiness. Money and success don't bring lasting happiness. Happiness depends on ourselves. In other words, we make our own happiness. Some people believe that if they are _ , they will be able to do anything they want, which means happiness. On the other hand, some people believe that holding a high position in the government is happiness. In this way, you have not only money, but also many other things which can't be bought by money. However, other people believe that having lots of money is not happiness, nor is holding a high position in the government. These people value their beliefs, or their intelligence, or their health. They think these can make them happy. Here are a few ways to help you be happier. The first secret of happiness is to enjoy the simple things in life. Too often, we spend so much time thinking about the future, for example, getting into college or getting a good job, that we don't enjoy the present. You should enjoy life's simple pleasures, such as reading a good book, listening to your favorite music, or spending time with close friends. People who have close friends usually enjoy happier and healthier lives. The second secret of happiness is to be active. Many people go dancing or play sports. People can forget about their problems and only think about the activities. Finally, many people find happiness in helping others. According to studies, people feel good when they volunteer their time to do many meaningful things for other people. If you want to feel happier, do something nice for someone. You can help a friend with his or her studies, go shopping to get food for an old neighbor, or simply help around the house. Now maybe you know how to find happiness! The passage mainly tells us _ . A) how to find happiness B) how to save happiness C) to do something good for others D) to value our beliefs or health
(Answer)
A