In what sentence has a shift verb tense

what are the sentences? i can try to help

invention of the washing machine

in the past, people used sticks and stones or scrub boards to clean their clothing. as it was sweaty, backbreaking work, we owe a world of to james king because he created the model for the modern washing machine in 1851. the most important issue was that this machine cleaned clothes while a person cranked the handle. doing this made people who used it develop strong muscles in their arms. later, in 1908, alva j. fisher created an electric washing machine named thor. this one was not the first automatic washing machine. however, it was one of the most popular models at the time.

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serve the people! ,” smoothly translated by julia lovell, offers an initial sample of yan lianke’s writing to an english-speaking audience. a bluntly drawn, mildly erotic fable, it teases mao zedong by poking fun at a true believer who obeys the chairman’s precepts too literally. to a western sensibility, the broad strokes of yan lianke’s humor would seem to pose little risk of inciting rebellion, whether of the flesh or of the body politic. but then, part of the book’s attraction is that it doesn’t have a western sensibility. it lets the reader see — or rather, intuit — what jokes chinese officials don’t consider funny, and how very little it takes for a writer to be branded an incendiary in 21st-century china, more than three decades after the death of mao, a decade after the death of deng xiaoping and seven years since china entered the world trade organization, a move that would seem to signal a willingness (however wary) to mingle with the rest of the world.