material reciprocity

• 实质互惠

material reciprocity的用法和样例：

例句

1. Reciprocity needs more communications from both countries.
   互惠互利建立在两国加强沟通的基础上。
2. The reciprocity rule explains my feeling of indebtedness to Torre.
   就是互惠这一条，让我觉得欠了托尔一分人情。