disk of variable thickness

例句：

1. 1. The computer uses a hard disk to store data.
   计算机使用硬盘来存储数据。
2. 2. She bought a new disk for her computer.
   她为她的电脑买了一个新硬盘。
3. 3. The disk is cracked and needs to be replaced.
   这个硬盘裂了，需要更换。