basic cover

例句：

1. 1. The basic cover of this book is very thick.
   这本书的基础封面非常厚。
2. 2.The company's basic cover price is $500.
   该公司的基本报价是500美元。
3. 3. The new product has a basic cover that protects the device from dust and scratches.
   新产品有一个基本的保护套，可以防止设备受到灰尘和划痕的侵害。