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Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions.    In this era of increased global warming and diminishing fossil fuel supplies, we must begin to put a greater priority on harnessing alternative energy sources. Fortunately, there are a number of readily available, renewable resources that are both cost-effective and earth-friendly. Two such resources are solar power and geothermal power. Solar energy, which reaches the earth through sunlight, is so abundant that it could meet the needs of worldwide energy consumption 6,000 times over. And solar energy is easily harnessed through the use of photovoltaic cells that convert sunlight into electricity. In the United States alone, more than 100,000 homes are equipped with solar electric systems in the form of solar panels or solar roof tiles. And in other parts of the world, including many developing countries, the use of solar systems is growing steadily. Another alternative energy source, which is abundant in specific geographical areas, is geothermal power, which creates energy by tapping heat from below the surface of the earth. Hot water and steam that are trapped in underground pools are pumped to the surface and used to run a generator, which produces electricity. Geothermal energy is 50,000 times more abundant than the entire known supply of fossil fuel resources. And as with solar power, the technology needed to utilize geothermal energy is fairly simple. A prime example of effective geothermal use is in Iceland, a region of high geothermal activity, where over 80 percent of private homes are heated by geothermal power. Solar and geothermal energy are just two of a number of promising renewable alternatives to conventional energy sources. The time is long overdue to invest in the development and use of alternative energy on a global scale.    What is the main topic of this passage?

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Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.    George Washington Carver showed that plant life was more than just food for animals and humans. Carver's first step was to analyze plant parts to find out what they were made of. He then combined these simpler isolated substances with other substances to create new products.    The branch of chemistry that studies and finds ways to use raw materials from farm products to make industrial products is called chemurgy. Carver was one of the first and greatest chemurgists of all time. Today the science of chemurgy is better known as the science of synthetics. Each day people depend on and use synthetic materials made from raw materials. All his life Carver battled against the disposal of waste materials and wamed of the growing need to develop substitutes for the natural substances being used up by humans.    Carver never cared about getting credit for the new products he created. He never tried to patent his discoveries or get wealthy from them. He turned down many offers to leave Tuskegee Institute to become a rich scientist in private industry. Thomas Edison, inventor of the electric light, offered him a laboratory in Detroit to carry out food research. When the United States government made him a collaborator in the Mycology and Plant Disease Survey of the Department of Agriculture, he accepted the position with the understanding that he wouldn't have to leave Tuskegee. As an authority on plant diseases - especially of the fungus variety - Carver sent hundreds of specimens to the United States Department of Agriculture. At the peak of his career, Carver's fame and influence were known on every continent.   With what topic is the passage mainly concerned?

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Read the following passage and mark the letter A, B, C or D on you answer sheet to indicate the correct answer to each of the questions.  The Urban Gardener      Cities are home to skyscrapers and apartment buildings, and it's rare to find wide, open spaces within them. With limited space for parks and gardens, architects and city planners often find it challenging to incorporate greenery into neighbourhoods.       One creative solution is to grow plants on unused areas like walls or rooftops. It's a popular idea, and now rooftop gardens and green walls have been spouting up in cities around the world. There are many benefits to having green spaces to the urban landscape. Adding gardens to rooftops or walls can create a pleasant environment - what was once a grey cement wall can become a colourful, blooming garden. The CaxiaForum art gallery in Madrid, Spain, is a famous example - one of its walls is covered with 15,000 plants from over 250 different species.       In other cities, green walls are being used more functionally, to cover up construction sites and empty buildings and to prominently decorate the lobbies of office buildings. Using plants to cover walls and rooftops can also keep cities cooler in the summer. Buildings and roads absorb the sun's heat and hold it, causing a building or neighbourhood to stay warmer longer. Plants, on the other hand, provide an enormous amount of shade. There is evidence that growing a roof or wall garden can lower a building's energy costs. Many cities offer tax discounts to businesses with these features. In Ne City, public schools plant rooftop gardens that can reduce heating and cooling costs.      In addition to saving the school money, teachers and parents love the gardens because of their educational value - it's a fun and healthy way for their kids to investigate the world around them. “For the children, it's exciting when you grow something edible," said Lauren Fontana, principal of a New York public school.       These green spaces are also used to grow food. In recent years, rooftop gardens have slowly been included in the "local food movement". This is based on the concept that locally grown food reduces pollution since it does not have to be transported far. Vegetables are being grown in rooftop gardens by schools, churches, neighbourhoods and even restaurants. Chef Rick Bayless serves “Rooftop S his restaurant in Chicago, USA, using only ingredients grown in his rooftop garden. Rooftop gardens and green walls may require a bit more effort to grow and maintain. However, hard work always brings rewards, and with green spaces, the rewards are plentiful. What is this passage mainly about?

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