If that's all it knows, then in that scenario there is no building or anything else; it continues a trajectory both forward in time and backward in time, and it says that whatever seconds, one second before you set your clock to 0, it would've been on the ground.

如果是这样,在那种模式下,没有楼房或者别的什么,物体的运动轨迹可以沿时间可以向后延伸,也可以向前延伸,不管时间取什么值,在零点前一秒时,物体就在地面上

耶鲁公开课 - 基础物理课程节选

What happens after the elections in Europe and the U.S. will set the trajectory of the next decade, be it an era of recession or an economic rebirth.

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Set against that trajectory, Mr Bush's proposals are extremely modest.

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Even if a plan of action can be agreed between the two political parties ahead of the election next year the growth path of debt is already set on an upward trajectory.

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