How can you prevent mosquitoes from breeding at home and in school?

The obvious thing to do is if they are breeding in a pesky spot is to either exterminate them or just squish them...

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Mosquitoes breed in standing (not running) water. Find the water, and eliminate it, and you will reduce the number of mosquitoes by quite a bit. Change water in birdbaths daily, check trays under outdoor flowerpots, check buckets, folds in plastic tarps, etc.