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XIII. Combine each pair of sentences, using the words/ phrases in brackets. You can make some changes. 1. We are unable to see the stars in the sky.Light pollution occurs.(makes) 2. Glass panels, windows, lawns and roofs make light pollution worse. They reflect artificial and sun light. (because) 3. All sound are not noise. Noise is any sound that is unwanted and goes beyond its certain limit, for example, above 80 decibels. (because) 4. More and more noise is created by modern civilization. It has now become a major environmental pollutant, especially in urban areas. (so) 5. Contamination in the air happens. There is acid rain which damages soil, vegetation and aquatic life of the region. (causes) 6. Noise pollution is one of the major causes of stress and anxiety. People suffer from stress and anxiety. (because of) XIV. Based on the context, make conditional sentences type 2 from the clues. 1. My home hasn't installed a solar water heater. If/ my home/ install/ a solar water heater/ we/ save a lot of energy. 2. Not all households in Viet Nam turn off lights during the Earth Hour. If/ all households/ Viet Nam/ turn off lights/ the Earth Hour/ we/ save enough electricity/ develop our rural areas. 3. Some students in our school still throw litter on the school ground. If/ students/ our school/ not throw litter/ the school ground/ our campus/ look/ greener fresher. 4. People use aluminum cans instead of glass bottles. If/ people use/ glass bottles/ they/ use/ again and again. 5. Our school ground is large but we don't have a wind turbine. If/ we/ install/ a wind turbine/ our school/ become/ more eco-friendly. 6. People don’t use organic fertilizers. If/ people/ use/ organic fertilizers/ they/ prevent/ land pollution. 7. A large number of people ride their motorbikes to work. If/ people/ ride/ bikes/ they/ keep/ air/ less polluted