甘草( )
A.断面有淡黄色小点排列成数轮同心环B.断面具放射状纹理C.断面有“星点”D.断面有一条凸起的环纹或条纹E.断面有“云锦花纹”
参考答案:B
Sales went up in the stores during December, but ______ again after Christmas.
A.dropped off
B.dropped out
C.dropped over
D.dropped on
普通数控铣床程序与加工中心编程的主要区别于()。