皮皮学，免费搜题
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搜题
【单选题】
下列变化过程中属于物理变化的是（ ）A.
天然气燃烧
B.
KMnO 4 加热分解
C.
CO 2 使澄清石灰水变浑浊
D.
冰块受热变成水蒸气
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参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【多选题】What did Einstein and Edison have in common?
A.
They faced immense obstacles and extreme criticism
B.
They were called “slow to learn” and written off as idiots by their teachers.
C.
They overcame their childhood persecution and went on to achieve magnificent discoveries.
D.
Their parents believed in them and worked intensely with their sons.
【简答题】低碳钢试样的应力一应变曲线可以大致分为4个阶段。阶段I为( )阶段;阶段II为( )阶段;阶段III为( )阶段;阶段IV为( )阶段。