We know we can’t do it alone.

我们知道我们不能单独做好这件事。

youdao

You can not do it alone.

你不可能一个人有所成就。

youdao

Please help me; I can't do it alone.

请帮帮我，我一个人做不了这件事。

youdao

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

We can't do it alone, though, and it's gratifying to see other states following our lead.

CENTERFORSECURITYPOLICY: Terror-free investment gathers steam

Mr Ishiba is realistic enough to know that the LDP could not do it alone.

ECONOMIST: An unusual militancy is creeping into mainstream politics

As one put it, all this proves is that the states can't do it alone.

NPR: Mass. Cuts Health Benefits For Some Immigrants