加热高锰酸钾能分解出氧气．某同学欲制备16g氧气，请帮他计算一下，至少需要加热分解多少克高锰酸钾？

改革开放后，我国的就业和社会保障制度开始调整、变革。以下选项正确的是(    )

①从前的“铁饭碗”逐步被打破②自主择业逐渐被人们所接受 ③开始建立社会养老保险制度 ④医疗保险制度改革迈出步伐       

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                                                                                              七律·长征
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                                                                                           乌蒙磅礴走泥丸。
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