从隔壁房间能听到柔和的低语声。

A soft ___murmur of conversation could be heard from the adjacent room.

她低声回应，以免打扰他人。

She responded with a gentle ___murmur to avoid disturbing others.

溪水持续的低语声提供了舒缓的背景噪音。

The constant ___murmur of the stream provided a soothing background noise.