核心词议：
n. 有用；有效性；有益
usefulness 基本解释
n. 有用，有益，有效；效能
速记方法
知识扩展
中文词源
中文词源： usefulness
精选例句
1、 There are doubts about the usefulness of these tests.
这些试验是否有用，人们有所保留。
常见考点例句：
- So both their use and their usefulness were extremely limited .
- 因此这些检测的使用和有用性都极其有限。
- The selection of locations also features tongue-in-cheek descriptions so users can assess the usefulness of each category .
- 对区域选择的说明看上去还挺像回事儿，用户可以由此进入有用的目录。
- Usefulness aside , this extension will let you see the date that any user joined the micro-blogging service .
- 撇开是否有用不谈，这个扩展能让你知道这个微博服务中任何用户的创建日期。
- Usefulness , he said , is a large part of what makes the paper he most admires beautiful .
- 他说，纸之所以如他赞赏的那样美丽，很大一部分原因是因为纸有用。
- How can this problem be solved by retaining the seemingly usefulness of global variables while keeping to object-oriented programming 's strict standards ?
- 如何这样解决这个问题：保留这看起来有用的全局变量同时符合面向对象的程序设计的严格标准？
