usefulness
n. 有用；有效性；有益
例句
There are doubts about the usefulness of these tests.
这些试验是否有用，人们有所保留。
《牛津词典》
Man early learned the usefulness of weapons.
人类很早以前就知道了武器的用处。
《新英汉大辞典》
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.
如果一个交互式计算机屏幕要在实用性上与白板相匹配，它必须在手臂长度范围和横跨房间范围内是可视的。
