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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.       An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous changes. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled- a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.       Many of more important air pollutants, such as sulfur oxides, carbon monoxides and nitrogen oxides are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.       However, human production usually occurs in a localized area, such as a city. In such region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however has a natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm.  What does the passage mainly discuss? 
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.        Stella McCartney was born in 1972, the daughter of pop star Sir Paul McCartney. She is the youngest of three sisters. One sister is a potter and the other sister does the same job as their mother used to do - she works as a photographer. Stella's brother, James, is a musician. Stella first hit the newspaper headlines in 1995 when she graduated in fashion design from art college. At her final show, her clothes were modeled by her friends, Naomi Campbell and Kate Moss, both well-known models. Unsurprisingly, the student show became front-page news around the world. Stella hadn't been in the news before as a fashion designer but she had spent time working in the fashion world since she was fifteen. In March 1997, Stella went to work for the fashion house Chloe. People said the famous fashion house had given her the job because of her surname and her famous parents but Stella soon showed how good she was. She designs clothes which she would like to wear herself, although she's not a model, and many famous models and actors choose to wear them. In 2001 Stella started her own fashion house and has since opened stores around the world and won many prizes. A lifelong vegetarian, McCartney does not use any leather or fur in her design. Instead, she uses silk, wool and other animal-derived fabrics.  (Source: Adapted from Objective PET) Which of the following is NOT true about Stella’s family?