swing: implies a movement through an arc of something attached at one end or one side: the door suddenly ~ open.   还表示秋千、巨大影响


sway: implies a slow swinging or teetering movement: the bridge ~ed a little and then fell.   (teeter摇晃蹒跚不稳: unsteady, seesawing movement,如an inebriated man teetering as he stands一个醉酒的人站得摇摇晃晃)


oscillate: stresses a usually rapid alternation between extremes of direction: a fan that ~s will cool more effectively.


vibrate: suggests the rapid oscillation of an elastic body under stress or impact: the ~ strings of the piano.  （elastic能伸缩，如slacks that come with an elastic waistband长裤有可伸缩腰带）


fluctuate: suggests a constant irregular changing of level, intensity, or value: monetary exchange rates ~ constantly.


waver: stresses an irregular motion suggestive of reeling or tottering: his whole body ~ed as he crossed the finish line.  (reel来回旋转失去平衡: to turn round and round or be thrown off balance,如a boxer reeling from the blow拳击手被打得晕头转向，即被打懵）  （totter蹒跚摇摇晃晃,如he tottered before he fell他走得摇摇晃晃，然后摔倒了）


undulate: suggests a gentle wavelike motion: an ~ing sea of grass.


swing摆动: 指一端被固定的物体在弧线上移动，sway也是摆动: 慢慢摆动来回摇晃， oscillate振动: 强调在两个极端之间快速交替，vibrate也是振动:  指弹性物体在压力冲击下快速振动(rapid oscillation)，fluctuate震荡: 持续不规则改变，如高度强度价格， waver摇晃：表示不规则晃动(totter)或转动(reel)，undulate波浪般起伏: 像波浪一样轻微上下摆动，还常用于麦浪地形。


记忆方法: 1）首字母想成VOW FUSS vow吃惊, fuss忙乱==>导致摆动


         2）摆动的意思是往返上下来回的移动mean to move to and fro, up and down, back and forth.