usefulness

increase usefulness 增加用途

usefulness index 實用性指數

Usefulness Pair 有效性對 ^[1] 

Man early learned the usefulness of weapons.

人類很早以前就知道了武器的用處。

There are doubts about the usefulness of these tests.

這些試驗是否有用，人們有所保留。

If an interactive computer screen is to match a whiteboard in usefulness, it must be viewable from arm's length as well as from across a room.

如果一個交互式計算機屏幕要在實用性上與白板相匹配，它必須在手臂長度範圍和橫跨房間範圍內是可視的。 ^[1]