SALT LAKE CITY, March 1, 2010 --- Like silkworm moths , butterflies and spiders, caddisfly larvae spin silk, but they do so underwater instead of on dry land. Now, University of Utah researchers have discovered why the fly's silk is sticky when wet and how that may make it valuable as an adhesive tape during an operation. "Silk from caddisfly larvae may be useful some day as a medical adhesive for sticking wet tissues," says Russell Stewart, an associate professor of bioengineering and principal author of a new study of the fly silk's chemical and structural properties. "I picture it as sort of a wet Band-Aid, maybe used inside in operations --- like using a piece of tape to close a cut," he adds. "Gluing things together underwater is not easy. Have you ever tried to put a Band-Aid on in the shower? This insect has been doing this for 150 million to 200 million years." There are thousands of caddisfly species worldwide. Some species spend their larval stages developing underwater, and build an inch-long, tube-shaped case or shelter around themselves using sticky silk and grains of rock or sand. Other species use silk, small sticks and pieces of leaves. Each larva has a head and four legs that stick out from the tube.The larval case gets wider as the larva grows.A caddisfly larva eventually pupates as it develops into an adult fly and then hatches. Caddisflies now live around the world in waters ranging from fast streams to quiet low lying wet land. The caddisflies'adaptation to diverse habitats is largely due to the inventive use by their larva of underwater silk to build complex structures for protection and food gathering. Caddisflies fall into two groups. Some build their case and then drag it along with them underwater as they search for food. Some build a shelter glued to a rock,with a silk net to catch passing food. According to Russel Stewart, caddisfly larvae _ . A) can spin silk underwater or on dry land B) are worth researching C) are quite different from butterflies and spiders D) have been widely used in the medical field
B
With the start of the new term, students around the country exchange their fun and fashionable clothes for boring school uniforms. But not all campuses are fashion deserts. Colorful sports shoes, school bags, T-shirts and even drink containers are breathing life into campuses. _ especially when we are doing morning exercises on the playground," and Qing Pei, a Senior 2 students from Shanghai Qibao High School. "But boys wear different sports shoes and girls have different decorations in their hair. These are the areas where you can express yourself," said Qing. Although it might be strange for boys to talk about fashion, they do care about what they wear in school, especially shoes, according to Qing. "Nike and Adidas basketball shoes, although they are still the must-have items for many of my friends, are becoming out-of-date," Qing added. He explained, "Since Liu Xiang ran so fast in Athens, running shoes are becoming popular in this autumn." "Still in fashion are the various baseball caps and American-style T-shirts with some English words printed on them," said Qing. Besides sports shoes and T-shirts, styles and colors of schoolbags are another chance for students to express their taste in fashion. Some bags are made more eye-catching by decorating them with small dolls. Other fashionable items are colorful drink containers, which are now popular with girls this term. "Some teachers are surprised to see a teenager sucking a bottle like this at school and criticize it as childish regression . But some girls just love it," said Yang Rui, a Senior 3 student. How do girls express themselves on campus? A) They wear different spots shoes. B) They wear school uniforms. C) They have different decorations in their hair. D) They drink coffee from colorful drink containers.
C
Q: My life began similarly to most children but I grew up without knowing what a father or mother was. No one was there to teach me how to tell right from wrong. Because of this, I got into some bad habits and spent seven years as a boy on the street. When I was 20, I was taken in a rehab clinic . Inside I met Bill, my counselor . He taught me a lot of things. The main thing was the gift of giving. It was the night before an important test and I was very nervous. Bill invited me to go out for a walk to relax me. As we walked and talked, Bill suggested we should go for a coffee. I told him I had no money when I got paid, and I offered to pay him back. He stopped then and looked at me in a serious, but loving way and said he was doing this because he wanted to. Then he said, "One day when you'll be around someone who will need a coffee, you'll be able to buy it for them. That's how you can pay me back." I'm a primary school teacher now. My job is simple and I can buy young people coffee now. Bill taught me how to offer help to others. Which of the following statements is probably right? A) The author was too stupid to tell right from wrong. B) Bill often offered his students coffee to please them. C) Bill had clever ways to teach his students. D) The author was often nervous before important tests.
A: C
Q: When I first saw the bookAlice in Lace, I thought I was going to like it. And as it turned out, I love it! I love books about life and being a kid. And Alice in Laceis just that kind. It's a humorous book about being thirteen and the problems kids might face. Alice and her friends get a strange assignment from their totally cool teacher, Mr. Everett. It was like playing the game of "Life," but you had to act it out. So Pamela is pregnant, Elizabeth buys a car and Alice gets married. Well, of course, Pamela wasn't really pregnant, but she walked around with a pillow under her shirt to get people's reactions. Elizabeth didn't really buy a car, but she went to the car lot and made the sales guy think she was. The whole class got assignments like these! I would love to do something like that for school. In the book Alice has a lot to think about. "Getting married is hard!" Alice says. She has to plan the ceremony, the honeymoon, find a place to live, pay for furniture and two months' rent and food. Maybe she and her "husband" could work it out -- if they were getting on fine! Although this book was funny, it really made me think about how problems like these could really mess up your life. Take teenage pregnancy for example. How could you have a baby and stay in school? You couldn't find a babysitter every day to stay with your kid. A child really consumes your life. I understand what the teacher was trying to do. He was trying to discourage the class from getting into these problems by giving them a glimpse of life. As someone about to become a teenager myself, I can say sometimes a story makes you think about what's up ahead. Overall, I would say this book is wonderful. My favorite part of the book is discovering that if I like it, there are seven other Alice books I can check out at my local library. I love this book, and I hope you will too. Why did Mr. Everett give his students such assignments? A) To encourage them to enjoy a meaningful life. B) To prevent them getting into those troubles at an early age. C) To make them realize the hardship of life. D) To teach them how to make a living.
A: B