at unit price

例句：

1. 1.The book is sold at a unit price of $20.
   这本书的单价是20美元。
2. 2. The coffee is served at a unit price of $3.
   咖啡的单价是3美元。
3. 3. The car dealership offers a unit price for the new model.
   汽车经销商为新款车提供了单位价格。