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设U={1,2,3,4,5}, A={1,2,3}, B={2,4}, 则A∪ ＝
设U={1,2,3,4,5}, A={1,2,3}, B={2,4}, 则A∪ ＝ ▲ ．
设U="{1,2,3,4,5}," A="{1,2,3}," B="{2,4}," 则A∪ ＝
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