Every body continues in its state of rest or uniform motion in a straight line, except insofar as it doesn't.

Every body continues in its state of rest or uniform motion in a straight line, except insofar as it doesn't.

每个物体在其静止状态或匀速运动状态下都保持直线运动，除非它不在直线上。

-- Arthur Eddington 爱丁顿