Read the following article and select the best answer. Article: Your cell phone holds secrets about you. Besides the names and numbers that you've programmed into it, traces of your DNA remain on it, according to a new study. DNA is genetic material that appears in every cell. Like your fingerprint, your DNA is unique to you --- unless you have an identical twin. Scientists today usually analyze DNA in blood,saliva , or hair left behind at the scene of a crime. The results often help detectives identify criminals and their victims. Meghan J. McFadden, a biologist at McMaster University in Hamilton, Ontario, heard about a crime in which the suspect bled onto a cell phone and later dropped the device. This made her wonder whether traces of DNA remained on cell phones --- even when no blood was involved. To find out, she and a colleague collectedflip-style phones from 10 volunteers. They collected invisible traces of the users from two parts of the phone: the outside, where the user holds it, and the speaker, which is placed at the user's ear. The scientists scrubbed(meaning "cleaned") the phones using a liquid mixture made mostly of alcohol. The aim of washing was to remove all detectable traces of DNA. The owners got their phones back for another week. Then the researchers collected the phones and repeated collecting traces on each phone once more. They discovered DNA that belonged to the phone's owner on each of the phones. Surprisingly, DNA showed up even in swabs that were taken immediately after the phones were cleaned. That suggests that washing won't remove all traces of evidence from a criminal's cell phone. So cell phones can now be added to the list of clues that can help a crime-scene investigation. Question: McFadden decided to find out whether people leave their DNA on their cell phones when she _ . - got her cell phone lost by chance - found a cell phone with blood on it - heard about a crime involving a cell phone - did research on cell phones
heard about a crime involving a cell phone

Read the following article and select the best answer. Article: "Gangnam Style" by singer Psy from Korea, is a popular song, but its extraordinary global success is really the result of its music video, which is a great piece of genius. On September 22nd, Guinness World Records listed "Gangnam Style" as the most-liked video in the history of YouTube. It's been performed at West Point (West-Point Style), and Google's CEO, has done the "Gangnam Style" horse dance at the company's office in Seoul. Even Samsung is trying to make Psy the new model for the latest type of fridge. The song's global popularity is such that the vast majority of people who enjoy it don't speak Korean, and have no idea what it is about. That's fine --- part of what makes "Gangnam Style" so fun is, like international pop music, the difficulty in understanding it. When we sing along, "Hey, sexy lady", we don't really know what we're singing about. The joy of _ is familiar to anyone who loves pop music from elsewhere. Anthony Lane, in his 2010 review of the Eurovision Song Contest, Only Mr. God Knows Why, used "Eurovision English" as one of its chief pleasures. It's "a complex tongue, spoken nowhere else, which raises the heartfelt poetry but absolute nonsense to a level of what sci-fi writers could only have dreamed. " In similar ways, "Gangnam Style" is just an over-the-top video where a fat man does a funny dance and sings repetitive words that don't make sense to most of us. But on the other, the magic of the song also lies in its funny dance, which reflects not just cultural morals specific to Korea, but cultural values easily recognizable to western viewers. This song's words may be in Korean, but its scenes are in clear American. The dance moves are simple enough to copy. Nonsense, in other words, forces us to let down our guards. It makes us relax, and asks us to let in all sorts of feelings from which, otherwise, we might distance ourselves. "Gangnam Style" happens to be so interesting because of its incomprehensibleness. Question: Some complex languages are used in pop music because _ . - singers regard it as one of the chief pleasures at the concert - they make the music hard to understand but poetic and attractive - the music can sound more pleasant and beautiful to the audience - people like listening to the music which makes special sense to them
they make the music hard to understand but poetic and attractive

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Read the following article and select the best answer. Article: A home computer not only helps children master the old ways of learning, but also opens up possibilities that simply aren't available in traditional education. Some software, for example, allows kids to make decisions and see the results in different situations. The World Wide Web encourages young minds to move easily from link to link, topic to topic. The best software draws children into learning by making them curious--what if I click on this picture, drag this over here, visit that website? Knowing how to use a computer also encourages a child's confidence. Kids figure out quickly that computers are powerful, and mastering the machine makes them feel grown-up. In turn, feeling confident on a computer often translates to academic confidence. Researchers have found that attitudes toward writing, for example, improve when students write on a computer. Perhaps most importantly, computers can enrich family life. Forget the idea that computer kids are separated. Children like to use the computer with adults and other kids, asking questions and comparing results. "The Internet is a unique opportunity to bring resources home, "notes Susan Haugland, PhD, Cape Girardeau, Mo. , author of Computer and Young Children:A World of Discovery. Although the benefits of computers are real, they have disadvantages, too. Kids can lose their way, wasting hours on mindless software of violent games. Just as parents have always helped children make good choices about everything from friends to food, books to TV, now we must make sure they get the best out of computers. Question: The passage is mainly talking about _ . - the disadvantages of children's using computers - the advantages of children' using computers - the development of computers - the fact that using computers makes children lose their way
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the advantages of children' using computers