A:进出口均为工业制成品
B:进出口都是初级产品
C:进口初级产品,出口工业制成品
D:进口工业制成品,出口初级产品
下列有关鉴别二氧化碳、氧气的方法错误的是( )
— Excuse me, have you seen _______ umbrella here?— Yes. Is it _______ beautiful blue one? I saw it here just now.