utility function的用法和樣例：
例句
- In the first part of this paper, we introduce briefly the background and recent research of recursive utility.
本文第一章首先對遞歸效用函數的背景及研究近況作了一個(gè)簡(jiǎn)要的介紹。 - So people begin to find out if there is another utility which is more practical and less complicated.
于是，人們開(kāi)始研究是否有其他更切合實(shí)際但又不至于過(guò)分復雜的效用函數。
