这段录音我保存为MP3格式，这样文件会更小。

I saved this recording in ___MP3 format to make the file smaller.

我把这首歌下载为MP3格式。

I downloaded this song as an ___MP3 file.

我下载了一个可以播放mp3文件的新应用程序。

I downloaded a new app that can play ___MP3 files.