be obligatory on

• prep. 应尽的(不可推卸的)

例句

用作介词 (prep.)

1. It is obligatory on every citizen to safeguard our great motherland.
   保卫我们伟大的祖国是每一个公民应尽的义务。
2. It is incumbent on you to give a father's advice before your son leaves home.
   在儿子离家之前给他一点忠告，是作父亲应尽的义务。