Sony has sold 385 million Walkman machines worldwide in 30 years as it evolved from playing cassettes to compact disks then minidisks - a smaller version of the CD - and finally digital files.

索尼在30年卖了385百万个随身听录音机机器全世界，它从演奏卡式磁带演变了对雷射唱片然后迷你激光唱片- CD的一个更小的版本-和最后数字式文件。

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