grumble

n. 怨言,满腹牢骚
v. 呻吟,喃喃地说出

They will grumble about having to do the work.

他们将为不得不干那项工作而抱怨。

He has everything he needs, but he is still full of grumbles.

他需要的一切都得到了，却还牢骚满腹。