Ключевые слова: background, beautiful, blue, cloud, concrete, construction, dam, drain, engineering, environment, fall, flow, flowing, gate, grass, green, greenpeace, gushing, lake, landscape, liquid, motion, mountain, nature, open, outdoor, outdoors, park, people, pipe, plant, power, reservoir, river, sky, spurt, stream, structure, summer, supply, technology, travel, tree, tube, tubing, view, wall, waste, water, waterfall,