The actions that are initiated by pressing the five-way navigation button may vary significantly
based on (1) the user’s location within the menu structure, and on (2) a particular action item of
interest (of many) on one individual screen. Focus refers to a way of identifying that single item
(from possibly several items) on the LCD screen.
大致意思：操作仪器要通过一个五向按钮，但因为两个原因使操作有所不同（1）是用户所在当前菜单位置，这个（2）就让我头大，不知他想说什么。最后那句是说当前项就是那个在屏幕上明显与其他选项区分开的的选项。 ……
