n the quality of being of practical use
n. 有用, 有益
[经] 有用, 有用性
1. The usefulness of this tool cannot be underestimated.
这个工具的实用性不容小觑。
2. She explained the usefulness of learning a second language.
她解释了学习第二语言的实用性。
3. The usefulness of technology in education is very clear.
科技在教育中的实用性非常明显。