今天我们要学的词是mandatory. Mandatory is spelled m-a-n-d-a-t-o-r-y, mandatory. Mandatory指“强制性的，必须的”。比如，mandatory retirement age 强制退休年龄。

Bulgaria's Minister of Regional Development is calling for the introduction of mandatory insurance for private residencies and all privately-owned buildings. 保加利亚地区发展部部长提出，应要求该国的私人住宅和全部私有建筑一律购买保险。The New York City Council is considering a new bill that will make it mandatory for all bikers to wear helmets.纽约市市议员正在考虑一项新议案，硬性要求纽约市每个骑自行车的人都必须佩戴头盔。好，今天我们学习的词是mandatory, mandatory, mandatory.....