不亦乐乎

tā zhěng tiān dōng bēn xī pǎo máng dé bù yì lè hū

他整天东奔西跑，忙得不亦乐乎。

On the go day in, day out, he is awfully busy.

wèi le dà jiā de lì yì tā měi tiān máng dé bù yì lè hū

为了大家的利益，他每天忙得不亦乐乎。

For the interest of all of us, he is awfully busy rushing about all day long.