【文章內(nèi)容簡介】 s rich in historical sites C. Detroit tourists are fascinated by its industry D. Detroit tourists are mainly attracted to new streetcar system 48. The purpose of the article is mainly to ________. A. pare top travel destinations B. remend some lesserknown destinations C. show how industrial and historic cities attract visitors D. inform us of some most popular travel destinations for 2018 B Drones（無人機） are slowly starting to bee part of our everyday lives. They used to be just known for helping create the action shots used in online videos and movies, but creative new ways to use drones are being invented all the time. Just take a look at this latest use: A solarpowered “transformer drone” has been developed by scientists from the University of Minnesota. US. Its aim is to make farmers’ work easier by letting them survey their crops from the air. The drone can take off like a helicopter, then change its shape midair to fly like a plane. The design means it can take off almost anywhere and hover（懸停）during flight to get a stable view of the land below. Despite its large wingspan of meters, the drone weighs just under 4 kilograms. Thanks to solar cells on its wings, it has enough power to fly nonstop during the daytime. It’s designed to be used by farmers to spot plant disease, manage water use and even spray pesticides in the exact place needed, reducing waste. The transformer drone is but a small part of a bigger picture. When asked what a drone looks like, most of us would probably picture a remotecontrolled toy, or perhaps a large, unmanned military aircraft. But those images could soon be quite different, as drones are being increasingly smaller and cheaper to make. They can now gather in groups of hundreds to fly like a flock of birds. Known as swarms（集群） , they’re seen as the next step forward in the drone industry. Swarms are clever. There is no leader in a swarm because it is a selfanizing system in which each drone is equal. This allows each drone in a swarm to search an area efficiently, or for the whole swarm, to fly together without colliding（碰撞）with one another. And only one operator is needed to control the whole swarm. Swarms are also tough. One missile（導彈） can bring down an aircraft, but a swarm can lose dozens of members and keep going. In fact, we have already had the luck of seeing swarms of drones in real life. In February, 300 drones made by US tech pany Intel formed a swarm in the shape of the American flag during Lady Gaga’s Super Bowl halftime show, lighting up the night sky. And Chinese pany EHang recently used 1,000 drones to display a map of China and the Chinese character for “blessings”. In the long term, as researchers at Harvard’s Wyss Institute predict, small swarming drones might bee as much a part of our environment as insects. Their RoboBee project is developing tiny drones smaller than a paper clip to collect weather data. So maybe in the next few years, our skies will be filled with thousands of drone swarms. 49. Which of the following statements is TRUE according to the article? A. Transformer drone was designed to help farmers predict local weather. B. Transformer drone can fly all year around without stopping. C. Transformer drone can check on plants from the middle of the air. D. Transformer drone is very tiny and works in large groups. 50. We can conclude from the article that drone swarms ________. A. are mainly used as military aircraft B. work well thanks to the teamwork of many operators C. have an advantage because of their selfanization D. are efficient with a smart and powerful leader in a swarm 51. We can learn from the last three paragraphs that ________. A. Lady Gaga was the first person to have used drones in a performance B. the RoboBee project is based on our understanding of birds’ flying patterns C. the large number of drones has bee a threat to our environment D. the spread of drones will benefit human beings in various ways C Maddie Hoffman is battling against epidemolytic ichthyosis her skin can grow up to ten times faster than normal, peels（剝落） and bees so dry that she can’t move. Each day she undergoes a twohour routine to remove dead skin cells and protect her from catching a life threatening infection. Her mother, Emily, was told that her daughter may not survive after she was born. She wasn’t allowed to hold her daughter until she was seven days old in an isolation room and she had to wear gloves and a mask. She said, “It was visible at birth that she had ichthyosis and shortly after that all the layers of skin fell off in sheets. She was bright red and looked like a burn victim. The nurse told us, ‘You realize your baby may not survive?’ It was very scary.” Her mother’s concern Emily added, “she has one of the most severe form s of the condition, requiring aggressive and painful treatment administered for up to three hours every day. The buildup of scaling is her worst enemy. The more it layers up the more likely she is to have skin infections. As each hour goes by, her skin gets harder for her to move。 she gets drier and starts to flakeoff. There are days when she can hardly move. The most affected part is her feet. Any friction causes blistering （起泡） , and even socks and shoes affect her. We have a daily battle with her blisters and her not being able to work tirelessly to stop them from getting infected.” Bullied at school Emily said, “Bullying is a big deal for her. She goes through a lot of stares and teasing. Kids get nervous seeing her skin shedding and bully her about her smell caused by the skin buildup. Seeing people stare at her and look with disgust, as a mother, I feel heartbroken. That is why we try to speak out. Maddie wants to help children in general to stay motivated and positive. We try to teach others that it’s