Fill in the Blanks (Reading & Writing)

Recycling plants —processprocessingprocessedprocesses enormous quantities of mixed waste every year, separating materials such as glass, plastic and paper so that each can be —reprocessedreprocessingreprocessreprocesses into new products. Magnets and optical sensors are used to —identifyidentifyingidentifiedidentifies metals and different plastic types automatically, a process that would be far too slow if —donedoingdiddo by hand.