一个与另一个单独相对one-to-one

• 中俄学生一对一携手参观校园，并且在教室内互相学习对方的语言。

  Chinese and Russian students paired up to visit the campus and studied each other's languages in the classroom.

• 三峡工程全面施工后，确立了“一对一”的支援格局。

  After the construction of the Three Gorges Project was completed, a one-to-one support structure was set up.