exchange repulsion

例句：

1. 1. The company exchanged its old equipment for newer models.
   该公司用新的型号替换了旧设备。
2. 2.They exchanged pleasantries with each other before the meeting began.
   会议开始前，他们互相问候。
3. 3. Exchange rates fluctuate frequently, so it's important to check them before making a purchase.
   汇率经常波动，所以在购买前要检查它们。