step backward,step forward,step onward和step downward分别什么意思?

问题描述:

step backward,step forward,step onward和step downward分别什么意思?

1.step backward:倒退;返回;逐帧倒放
2.step forward:走出,向前进;站出来
3.step onward:向前一步
4.step downward:向下走