The only thing I can do is keep quiet and sit this one out.

我能做的只有保持沉默，坐等这件事结束。

《柯林斯英汉双解大词典》

This is dreadful, but the only thing that I can think to do about it is to urge people to keep out of other people's dreams by every means in their power.

这是非常糟糕的，我认为对于这件事我唯一能做的事就是敦促人们利用他们所能用的每一种方法远离他人的梦境。

youdao

I hope you can understand that if you do not study hard, you will be as useless as the old gardener who can only do this humble job!

我希望你明白，如果你现在不努力学习，将来只能跟这老园工一样没出息，只能干低贱、卑微的工作！

youdao

There was nothing I could do. When you have this kind of a problem, you can only take care of your body.

VOA: special.2010.08.09

You can only do this because it's reversible. What else do I know?

这一步,只对可逆过程成立，还有什么已知条件？

麻省理工公开课 - 热力学与动力学课程节选

The lesson that I had realized from this is that there is only so much you can do and only so many hours in a day.

FORBES: America's Existential Peril: 29 Years Old, In Debt, and Disheartened

If expanding these work-based visas is the only option then I fully endorse this proposal, but I think we can do better.

FORBES: How To Improve Immigrant Visas

Mr. GAFFNEY: ...profitable and so on, but they're only, I'm afraid, doing this at the moment because they can both do business with America and do business with its enemies.

CENTERFORSECURITYPOLICY: Transcript of CNBC Divest Terror debate