咕哝

例句：

1. 1. He kept mumbling to himselfas he walked through the park.
   他边走边自言自语。
2. 2. She was constantly murmuringin her sleep.
   她经常在睡梦中嘟囔。
3. 3. The old man mumbledsomething about his lost keys under his breath.
   老人低声嘟囔着关于他的丢失钥匙的事情。