He says even the biggest, richest countries cannot do it alone.

VOA: standard.2009.08.30

To say that somebody does something alone means they do it not in the presence of others.

就是说人孤独而死的意思是,他们死的时候身边没有别人的存在。

耶鲁公开课 - 死亡课程节选

If you tried to do one alone it would not work, so we decided to divide it up imperfectly and there may be some repetition between our two courses.

非要分开单独来学的话是不可行的,所以我们只能退而求其次,分割后的两门课可能会有重复的部分

耶鲁公开课 - 金融市场课程节选

It's not that we all really do die alone.

不是说我们真的是独自死亡。

耶鲁公开课 - 死亡课程节选