The upshot is that if the rider leans forward he travels forward, whereas if he leans backward the machine will stop and then go into reverse.
结果就是如果驾驶者向前倾斜身体它就向前行驶,可是如果他向后倾斜机器就会停止然后向相反方向行进。
2
The problem arose because astronomers had noticed that some planets in the sky seemed to stop, move backward and then go forward in a loop.
这个问题也就产生了,因为天文学家已经发现有些行星在天空似乎停止,向后移动,然后在一个循环。
3
The problem arose because astronomers had noticed that some planets in the sky seemed to stop, move backward and then go forward in a loop. Others appeared brighter at times and less bright at others.