购销差价
参考答案：指同一商品在同一时期，同一产品市场，商品的购进价格与销售价额之间的差额。
金属喷镀、热固化酚醛树脂漆对金属表面预处理的质量要求是( )。
A．F1
B．Pi
C．Sa3
D．Sa1
Could you please give me your e-mail address ______ you go? [ ]
A. as soon as
B. before
C. after
D. until
