1. There are doubts about the usefulness of these tests. 这些试验是否有用，人们有所保留。
2. Man early learned the usefulness of weapons. 人类很早以前就知道了武器的用处。
3. 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。
4. Whereas local collaborations sometimes persist past the point of usefulness, because of social or academic obligations, international ones can be cultivated and dropped more freely. 尽管由于社会或学术义务，地方合作有时会超出其有效性，但国际合作可以得到发展和放宽。
5. An experimental version of the traditional scholarly methods course was designed to raise students' consciousness about the usefulness of traditional learning for any modern critic or theorist. 传统学术方法课程的实验版本旨在提高学生对传统学习对任何现代批评家或理论家有用性的意识。
