Effectivity
n. 有效, 功效
🗣️ 情景例句
The old library building on Chestnut Street,
Chestnut街老图书馆，
I ought to stay at home.
我应该留在家中。
Mum or dad, of course, provide a regular supply of pocket money, but uncles and ants are always a source of extra income.
爸爸妈妈当然经常给孩子零花钱，但是，叔舅婶姨也是孩子们额外收入来源。