number of friction pairs

例句：

1. 1.The number of friction pairs between the two materials is crucial for understanding their interaction.
   两种材料之间的摩擦对数对于理解它们的相互作用至关重要。
2. 2.In order to improve the performance of the bearing, it's necessary to reduce the number of friction pairs.
   为了提高轴承的性能，有必要减少摩擦对数。
3. 3. The design of the gear system requires careful consideration of the number of friction pairs and their distribution.
   齿轮系统的设计需要仔细考虑摩擦对数及其分布。