+for A new accounting system will soon become mandatory for all departments. 不久所有部门将必须采用新的会计系统。

it is mandatory to do sth It’ s mandatory to wear a seat belt in the UK. 在英国按规定要系安全带。

a mandatory sentence The trial judge imposed the mandatory sentence of life imprisonment. 负责审理的法官依法做出终生监禁的判决。