另外，如果免费用户中升级的比例低于预期，还可以通过广告进一步补充这个模型。

In addition, this model can be further supplemented with advertising if the ratio of free users to upgrades is less than expected.

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你可以在为一首歌破费之前听足五遍，同时如果你每月花费五美元升级帐户，则能够免除广告的打扰并且享受无限畅听服务。

You can listen to a song five full times before having to pay for it, and a premium account without the ads and unlimited streaming ability is only five bucks a month.

youdao

有广告的基本服务是免费的，升级后的版本没有广告，而且有更高质量的声音效果，三十六美元一年。

A basic, ad-supported service is free; the upgraded version, with no ads and higher-quality audio, is $36 a year.

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