船的晃动让他感到恶心。

The ___motion of the boat made him feel sick.

喷气发动机引起的空气运动使窗户颤动。

The ___motion of the air caused by the jet engines makes the windows tremble.

观看云朵在天空中缓慢移动令人平静。

The slow ___motion of the clouds across the sky was calming to watch.