空间两条直线平行,则其轴测图中两条直线的轴测投影( )
A. 平行
B. 倾斜
C. 垂直
D. 三者都有可能
正等轴测投影图的轴间角均为多少?
A. 120°
B. 135°
C. 45°
D. 90°
正等测图的轴向伸缩系数错误的是
A. p=q=r=1
B. p=q,r=0.5
C. p=q=r=0.5
D. p=r,q=0.5
This new method not only saves time but also saves energy ________ operating on two batteries instead to four.
A. in
B. on
C. by
D. for