【单选题】Though high-priced, specialty goods still have customers because ________.
A.
consumers can afford specialty goods
B.
consumers buy them not just for their physical quality but also for recognition, status and so on
C.
consumers think that specialty goods are profitable
D.
consumers think that specialty goods last longer
【简答题】经过一、二、三象限的直线l在y轴上的截距为1,且与直线2x-3y+4=0所成夹角为45°,则l的方程为______.
【单选题】图纸中标注 4B 18,其中4表示( )。
【单选题】油水分离器的油份浓度检测是在下列____情况下不会被清水清洗。
【简答题】如图所示,已知抛物线y=ax 2 +bx+c过点A(-1,0),且经过直线y=x-3与坐标轴的两个交点B、C. (1)求抛物线的表达式; (2)若点M在第四象限内且在抛物线上,有OM⊥BC,垂足为D,求点M的坐标.
【简答题】常见的效度的类型有哪些A. 再测效度;B. 复本效度;C. 表面效度;D. 准则效度;E. 建构信度