我能听见门后传来低沉的说话声。

I could hear the low ___murmur of voices from behind the door.

她发出一声表示同意的低语作为回应。

She responded with a quiet ___murmur of agreement.

图书馆里持续不断的低语声是一种令人舒缓的背景噪音。

The constant ___murmur of conversation in the library was a soothing background noise.