The success of the system is not in doubt.

这种制度的成功确定无疑。

《牛津词典》

Then steam power entered the scene, putting the whole future of waterpower in doubt.

随后，蒸汽动力登上了历史舞台，让整个水力发电的前景一度遭到了怀疑。

youdao

The outcome was still in doubt.

结果仍不确定。

《柯林斯英汉双解大词典》

Even before this oil leak, BP's safety policies were in doubt following major accidents in Alaska and Texas in the past decade.

VOA: standard.2010.06.18

So, when in doubt, if you're having some weird character issue, odds are you need to escape it in some way.

如果你有拿不准的字符,可能就要用到转义字符了。

哈佛公开课 - 计算机科学课程节选

And in general, what I would say is, when in doubt, use parens. OK.

因此通常上，我会告诉大家的是，当有疑问的时候，请用括号，好。

麻省理工公开课 - 计算机科学及编程导论课程节选

That principle is accepted by the secretary of state and is not in doubt.

BBC: Abu Qatada: Government appeal bid rejected

The usual example is the Great Depression, but even that episode is in doubt.

FORBES: Can We Spend Ourselves From Recession To Prosperity?

Those were difficult times--when the future of the exchange's floor-based auction system was in doubt.

FORBES: Hot Seats