低吟

例句：

1. 1. She muttered a few words to herself as she walked away.
   她自言自语地走开时低声说了几句话。
2. 2.The old man muttered under his breath about the weather.
   老人低声抱怨着天气。
3. 3.They muttered among themselves about the unfairness of the situation.
   他们低声讨论着情况的不公平性。