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. McFadden decided to find out whether people leave their DNA on their cell phones when she _ . A) got her cell phone lost by chance B) found a cell phone with blood on it C) heard about a crime involving a cell phone D) did research on cell phones
C
Growing up, I knew I was different. My father had left and he never came back. As I later discovered, the abandonment triggered my anxiety attacks. I feared being alone, unwanted, unpopular, and unloved. My first attack came in a ninth-grade class: The teacher asked me to walk in front of the class, but I couldn't do it- I was soaked in sweat, shaking. My symptoms began every morning from the moment when I stepped inside the school building. Throughout my childhood, I was no stranger to the doctor's office. My mother tried everything she could in hope of a breakthrough. There were times I thought suicide could be the only way to make the pain stop. By age 16, I had shut down socially. Most of my peers were going to parties, playing sports, and dating. But I was a prisoner in my own home. Then one Sunday morning, my wake-up call came from a magazine article. Freddie Prinze, Jr. was on the cover. The article detailed the pain of losing his father at a young age. I felt as though I were reading my own life story. The only difference? He was now a success. That article inspired me to explore a new treatment option for myself. I wanted to turn my life around as well. So I hit the library and the Internet, and I began to realize how my negative thoughts controlled my physical well-being. Immediately, I made a plan to take charge of my life. Shortly after following the items I had listed, I was able to stop seeing a therapist. I never returned to high school, but I did go to college. After graduation, I pursued a career in television news. My relationships have changed for the better, too. I've made new friends and reconnected with many from my past The anxiety isn't completely gone, but whenever it returns, I know the feeling will pass, and know I have the power to change my life, only if I will give myself a chance. The writer wrote this story to tell us _ . A) anxiety attacks are not lasting if we have proper treatment B) we shouldn't keep ourselves away from the outside world C) we can change our lives if we give ourselves a chance D) fathers are not supposed to abandon their small kids
C
Q: My first experience of modern city life was quite impressive. I was very curious when I arrived in London. First, I noticed so many people were on a trip in a busy way. When I first saw the machine on the underground where you are expected to feed your ticket in and have to run through moving barriers , I was completely fascinated at it. Flashing with the light, the little green man, telling you when to cross the road, was also quite interesting, and so were those street advertisements which kept changing subjects as you look. In my native place, my life is so different from people's here. I am a market gardener from Makono, a village which is led by a market-managing group. People there usually walk two hours a day to get water from a well. What's more, I am used to going, for many hours, without drinking , so it was strange to be offered cups of tea all the time here in London. In my native place, on market days, I usually walk for several hours with my basket full of fruits and vegetables on my head, carrying them to the market for sale, to earn PS1per basket. Without the produce from my garden, I could not pay for education or healthcare for my children. Gardening is not a hobby for me - it's _ . But here people are planting something only to kill their leisure time. During our visiting-time in Britain, we visited some local government agencies, schools, churches and farms in Sussex, Scotland, Yorshire, Loncolnshire and Cambridgeshire, meeting people who were of the same profession as we are. Children in Burley-in-Wharfedale, Yorkshire, prepared a special get-together to greet us and we were also asked a lot about our life which was quite fascinating to them. For example, how we make our houses out of mud and how we get our water for our daily necessities, as well as for our garden. The most disadvantage in the writer's native place should be that _ . A) there are many market-managing groups for gardeners B) the lack of water makes the life there even harder C) people there like to travel about on foot for enjoyment D) people support themselves using the garden produce
A: B
(Question)
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. The passage is mainly talking about _ . A) the disadvantages of children's using computers B) the advantages of children' using computers C) the development of computers D) the fact that using computers makes children lose their way
(Answer)
B