阿光盘是一种光泽，圆盘，储存的信息。
A compact disk is a shiny, circular disk that stores information.
如果你已经使用过电脑并在里面储存了信息，信息会储存在这样的光盘上。
If you've already used the computer and stored information in it, that information will be on a disk like this.
一张DVD能储存较大数量的信息，主要是因为光盘较小的凹坑和紧密的轨迹相间隔，但是另外一个因素也发挥了作用，即压缩。
The greater amount of information stored on a DVD is chiefly due to the smaller pit size and tighter track spacing, but another factor comes into play, namely compression.
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