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Method 43 cases of aac which were treated from1999to2004were analyzed retrospectively .

方法对我们1999-2004年间收治的43例aac进行回顾性分析。

Nearly all downloadable music stores offer only unprotected and standardised mp3 or aac formatted audio , which can be played on any device .

几乎所有可供下载的音乐商店里提供的都是未设保护机制的标准mp3或者是aac格式的音频，它们能够在任何设备上播放。

The company announced that for $ 20 a year , users will receive unlimited storage space for their mp3 and aac music files .

亚马逊宣布，用户只需每年交付20美金，就可拥有无限储存空间来储存mp3和aac音乐文件。

I want to use them in another program that doesn 't recognize the aac song format that itunes prefers .

我想用另一个程序播放，但itunes主要使用的aac歌曲格式在里面不认。

Pandora encodes its songs using a high-efficiency aac codec , compared to the mp3 encoding used with last.fm . A 64kbps he-aac file is said to sound on-par with a 128kbps mp3 , providing the same level of quality , but at half the bandwidth .

pandora使用一个高效率aac编解码器来编码它的歌曲，一个64kbps的he-aac文件据说听起来跟128kbps的mp3一样，提供一样水平的质量，但频宽就只有一半。