oscillate

风扇的叶片左右摇摆，发出轻微的嗡嗡声。

The fan blades ___oscillate from side to side, making a soft humming sound.

老座钟的钟摆以稳定而有催眠感的节奏来回摆动。

The pendulum of the old grandfather clock ___oscillated with a steady, hypnotic rhythm.

走上舞台之前，她的情绪在兴奋和恐惧之间来回摇摆。

Her mood ___oscillated between excitement and dread before stepping onto the stage.