Time - barrels require filling, emptying and topping up - all take time and have a Labour cost.
时间-桶需要填充、排空加油——所有的花费时间和劳动成本。
2
Think of it like a jug of water: you can't keep emptying yourself out to look after children around you without filling yourself up again.
这就比如是一壶水：你自己都空空如也，拿什么去照顾孩子，非得把自己充满起来再说。
3
Filling and emptying containers and boxes, and stacking and knocking down multiple items such as cups, blocks and plastic rings forms part of your baby's learning about reach, grasp and release.