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smog - n. fog mixed with smoke : a cloud of dirty air from cars, factories, etc., that is usually found in cities
asthmatic - n. relating to or suffering from asthma (a physical condition that makes it difficult for someone to breathe)
park - n. a piece of public land in or near a city that is kept free of houses and other buildings and can be used for pleasure and exercise
nest - v. to build or live in a nest
undisturbed - adj. not moved, changed, touched, etc., by anyone or anything
catastrophic - adj. a terrible disaster
silver lining - idiomatic expression. something good that can be found in a bad situation
