reciprocal one-to-one correspondence

例句：

1. 1. The two companies have a mutually beneficial relationship.
   这两家公司拥有互利的关系。
2. 2. The teacher gave each student a reciprocal mark for their work.
   老师给每个学生一个互评分数，以评价他们的工作。
3. 3. The reciprocal of 4 is 8, which means that 4 times 8 equals 4.
   4的倒数是8，这意味着4乘以8等于4。