B1 Reading Practice Test 4

When Mateo's school in Lisbon announced that the roof would be turned into a garden, most students thought it was a joke. The roof was grey, hot and covered with old pipes. But their science teacher, Ms Costa, was serious. "A green roof keeps the building cooler in summer," she explained, "and it gives bees and butterflies a place to live." The class had to plan everything themselves. Mateo and his friends measured the space, looked up which plants can survive strong sun, and wrote a list of what they needed. They were not allowed to spend more than two hundred euros, so they asked local shops for help. A garden centre gave them soil, and a neighbour donated old wooden boxes. It took three Saturdays to finish the work. They planted herbs such as thyme and rosemary, as well as small flowers that attract insects. A simple system collects rainwater, which is used for watering. By the end of the summer, the roof looked completely different. Teachers noticed that the top floor was several degrees cooler than before. Even more surprising, butterflies appeared in July. "I never thought we could change a place like that," Mateo told the school newspaper. "Now I check the plants every morning before lessons."

The International Space Station, or ISS, travels around the Earth at about twenty-eight thousand kilometres an hour. It is so fast that it goes round the planet roughly every ninety minutes. As a result, the astronauts on board see around sixteen sunrises and sunsets every day. Living in space is very different from life on Earth. Because everything floats, astronauts have to fix their belongings to the walls with straps or tape. They sleep in small cabins, attached to the wall in sleeping bags so that they do not drift around. Eating is another challenge. Food comes in sealed packages, and drinks are sipped from bags with straws, because liquid would escape from an open cup. Astronauts also have to work out for about two hours every day. Without gravity, muscles and bones become weaker, so they use special exercise machines to keep their bodies in good condition. The rest of the day is filled with experiments, repairs and talks to students on Earth. Scientists are learning a great deal from the station. For example, studies about how plants grow without gravity may one day help to produce food on long space journeys. Several countries have worked together to build and run the ISS, and it has been visited by astronauts from more than twenty nations.

Aiko was good at maths, but she had never written a computer program before. When her teacher mentioned a coding contest for students under sixteen, she almost didn't sign up. "Everyone else will be better than me," she thought. Her best friend, Kenji, convinced her to try. The challenge was to create a simple game in one weekend. Aiko spent Saturday morning drawing her idea on paper: a cat that has to collect fish while avoiding puddles. Then she began typing the code. Almost immediately, nothing worked. The cat refused to move, and the fish disappeared at random. By Saturday night, she was close to giving up. Her older brother, who studies computer science, looked at the screen for a minute. "You've made a small mistake here," he said, "but I won't fix it for you. Read the line again." Aiko checked carefully and finally spotted a missing symbol. When she corrected it, the cat ran across the screen. She laughed out loud. On Sunday evening she sent in her game. She didn't win the contest, because first prize went to a boy who had made a music game, but the judges praised her creative idea and gave her a certificate. More importantly, Aiko had discovered something about herself. "A problem looks scary at first," she said, "but if you break it into small steps, it becomes much easier."