两同阻值的电阻并联时的总电阻为5Ω，串联时的电阻为20Ω，则该电阻阻值为（）Ω.
A.5
B.10
C.2.5
D.7.5
参考答案：B
小红细胞常见于（）
A.铁粒幼细胞性贫血
B.再生障碍性贫血
C.巨幼细胞性贫血
D.脾功能亢进
E.血型不合的输血后溶血
--Tibet, a part of China can not suddenly become its own country.
--_______. All the Chinese people are against it
A．Yes, it can
B．Yes, it can’t
C．No, it can
D．Certainly not
