a wheel fixed in position in the middle, designed for a hamster or other small animal to run round and round inside as exercise

At 3 a.m. I was awake listening to the rumbling of the hamster wheel. 凌晨三点，我还醒着，听着仓鼠转轮发出的轰轰声。

an activity that involves someone being busy all the time but never achieving anything important or reaching the end of a task

There's always something that needs to be done to the house. It's like a hamster wheel. 房子总有要修修补补的地方，就像仓鼠轮一样，没完没了。

Time spent just sitting on a train can be a rare chance to step off the hamster wheel and observe the world. 坐在火车上的时间是一个难得的机会，可以让你离开犹如仓鼠转轮般的日常生活，观察这个世界。