Now CD-ROM is already the standard PC configuration, in addition to re-loaded the erasable optical disc drive, or even DVD is a very common thing.

• 详细说明： 一台机器可能有不止一个CD-ROM驱动器。现在CD-ROM已经是PC机的标准配置，此外再装个可擦写的光盘驱动，甚至是DVD都是很常见的事情。