minor concept

例句：

1. 1.In the study of economics, a minor concept is the concept of marginal utility.
   在经济学研究中，次级概念是指边际效用的概念。
2. 2.The teacher explained the basic principles of physics to the students with a minor concept of quantum mechanics.
   老师用对量子力学的初步理解向学生们解释了物理学的基本原理。
3. 3. The author's book on environmental science introduced a minor concept of sustainable development.
   作者关于环境科学的书介绍了可持续发展的一个次要概念。