火车的摇晃运动使婴儿入睡。

The rocking ___motion of the train lulled the baby to sleep.

传送带的持续运动确保了高效生产。

The constant ___motion of the conveyor belt ensures efficient production.

钟摆的运动是规律且可预测的。

The ___motion of the pendulum is regular and predictable.