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有下列事件:①367人中必有2人的生日相同;②抛掷一只均匀的骰子两次,朝上一面的...
有下列事件:①367人中必有2人的生日相同;②抛掷一只均匀的骰子两次,朝上一面的点数之和一定>等于2;③在标准大气压下,温度低于0℃时冰融化;④如果a,b为实数,那么a+b=b+a.其中是必然事件的有( )
A.1个
B.2个
C.3个
D.4个
考点分析:
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