下列实验能够成功的是
A.通过溴水除去甲烷中的乙炔
B.将乙醇加热到170℃制备乙烯
C.加入浓溴水后过滤除去苯中的苯酚
D.加入氢氧化钠后蒸馏除去乙酸乙酯中的乙酸
答案:A
Windows 7 was created in 2009, ___ many computer lovers were interested and excited. [ ]
A. where
B. why
C. which
D. when
以基期成本费用水平为基础,结合预算期业务量水平及有关影响成本因素的未来变动情况,通过调整有关原有费用项目而编制预算的预算称为( )。
A.零基预算
B.弹性预算
C.静态预算
D.增量预算