Here in the United States, stand-alone record stores have given way to such alternatives as digital downloading which now accounts for about 20 percent of all recorded music sales.

VOA: standard.2009.12.25

Or at least,it is clear what your alternatives are; it's not clear which alternative would be any better.

至少就算选择明确;,哪个选择比较好的标准却不明确。

耶鲁公开课 - 死亡课程节选