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参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】Section BDirections: There are 2 passages in this section．Each passage is followed by some questions or unfinished statements．For each of them there are four choices marked A, B, C and D．You should de...
A.
deepen the economic inequalities
B.
sharpen the conflict between the rich and the poor
C.
cause the rich to share their technology with the poor
D.
limit the popularity of computers
【多选题】自由中子是不稳定的,它的平均寿命大约是900s,它能自发地发生放射性衰变,衰变方程是: 其中 是反电子中微子(不带电的质量很小的粒子)。下列说法中正确的是( )
A.
自由中子的衰变是β衰变,X是负电子
B.
有20个自由中子,半小时后一定剩下5个中子未发生衰变
C.
衰变过程遵守动量守恒定律
D.
衰变过程有质量亏损,所以能量不守恒