China is known ______ a developing country. [ ]
A. as
B. with
C. for
D. of
答案：A
以溴乙烷为原料制备1,2二溴乙烷，下列方案中最合理的是( )
A．CH3CH2BrNaOH水CH3CH2OH浓硫酸170℃CH2===CH2CH2BrCH2Br
B．CH3CH2BrCH2BrCH2Br
C．CH3CH2BrNaOH醇CH2===CH2CH2BrCH3CH2BrCH2Br
D．CH3CH2BrNaOH醇CH2===CH2CH2BrCH2Br
