解析：字面意思是-由 谁 付费
衍生寓意是 ：以牺牲某人为代价；捉弄某人。
英英释义为：if someone has a joke or enjoys themselves at your expense, they enjoy laughing at you.
例句
①Should architects continue to be trained for five years at public expense?建筑师是否继续受训5年的公费培训呢？
②I think he's having fun at our expense.我看他是在拿咱们寻开心。
③The orchestra has more discipline now, but at the expense of spirit.该管弦乐队现在更有纪律性了，但却失去了活力。
