一带电粒子平行磁感应线射入匀强磁场,则它作___运动; If a parallel magnetic induction line of the electric particle is injected into the uniform magnetic field, it will move ___.
A.直线; straight lines;
B.变速率圆周; speed change rate of the circumference;
C.匀速率圆周; uniform speed of the circumference;
D.螺线; spiral;