微需氧环境下环境的含氧量是（）
A.5%
B.10%
C.15%
D.20%
E.25%
参考答案：A
建设和谐社会的公平正义是指( )。
A．各方面利益关系得到妥善协调
B．各种矛盾得到正确处理
C．公平正义得到维护和实现
D．贫富差距得到大幅度缩小
A certain fraction is equivalent to . If the numerator of the fraction is increased by 4 and the denominator is doubled, the new fraction is equivalent to . What is the sum of the numerator and denominator of the original fraction ？（）
. If the numerator of the fraction is increased by 4 and the denominator is doubled, the new fraction is equivalent to 
. What is the sum of the numerator and denominator of the original fraction ？（）