圆内接正三角形的一条边所对的圆周角为( )
A.30°
B.60°
C.30°或150°
D.60°或120°
答案:D
________well prepared you are,you still need a lot of luck in mountain climbing. [ ]
A. However
B. Whatever
C. No matter
D. Although
在接触网带电情况下,严禁用棒条等物处理车辆顶部的扒车人员或物体,要立即向列车()汇报,在接触网停电后再进行处理。
A.运转车长
B.调度员
C.乘警
D.检车员