be useful to

• conj. 对 ... 有用处

be useful to的用法和样例：

例句

1. He seldom asked himself whether he liked such and such a man: he esteemed a man according to whether he was useful to himself.
   他极少问自己是否喜欢某某人，他只是按照某人是否对自己有用来估价他。