阴极直流电有促进骨折愈合作用,其电流强度宜选择()
A.5μA以下
B.10~20μA
C.5~10μA
D.20~25μA
E.25~30μA
参考答案:B
Only ______ allowed to take part in the speech contest in our class and so the rest ______ disappointed.
A.was John; were
B.John was; were
C.was John; was
D.John was; was
由于印刷工作流程比较复杂,制作工艺比较繁琐,使用的原料品种比较丰富,因此将印刷进行分类的方法有很多,如按()
A.印刷工艺分类
B.印刷程序分类
C.印刷原理分类
D.印刷色彩分类