"grumbling" in Chinese (Simplified)
抱怨嘟囔
Definition
用低声抱怨或发牢骚，通常是在对某事不满时。也可以指小声嘀咕些小问题。
Usage Notes (Chinese (Simplified))
常用于非正式场合，多指小抱怨或轻声不满。常和‘about’连用：'grumbling about the weather'。也可指物理声音，如肚子咕咕叫。
Examples
He kept grumbling about the cold weather.
他一直在**抱怨**天气很冷。
The students were grumbling about too much homework.
学生们在**抱怨**作业太多。
I heard my stomach grumbling during the meeting.
我在会议中听到自己肚子在**咕咕叫**。
"Enough with the grumbling, guys. Let's get started!"
“大家不要再**抱怨**了，我们开始吧！”
She walked away, still grumbling under her breath.
她走开了，嘴里还在**嘟囔**。
There's always some grumbling when the rules change.
规则改变时总会有人**抱怨**。