reciprocity principle
[英]ˌresəˈprɔsɪti:ˈprinsəpl
[美]ˌrɛsəˈprɑsɪti ˈprɪnsəpəl
互易原理
[例句]
Wing family needing " mutual reciprocity and mutual benefit " principle.
翼家人凭着"互惠互利"原则.