If they can't compare it to anything, it's doubtful that they will be able to see how your offering could work.

如果他们不能将你的产品和其他产品做任何比较，他们就很难明白你所提供的服务能逃起到什么样的作用。

youdao

It is even doubtful that those jobs will be saved, as cheap tires can be obtained from other places like Mexico instead.

我们甚至可以怀疑究竟这些工作岗位能否被挽救下来，因为便宜的轮胎也能从其他地方比如墨西哥进口。

youdao

But it is doubtful that the economics of online or mobile video will ever be as attractive as the economics of traditional television.

但人们怀疑因特网和手机视频经济不会永远像传统电视经济那样有吸引力。

youdao

It is not Dragon's Den, but it is doubtful that responsible charitable trusts or institutional investors will be committing wads of cash to a payment-by-results mentoring scheme for ex-offenders without good evidence that it can get those results.

BBC: A popular idea still on probation

It has to be doubtful whether the people of Greece, Spain, Portugal and Italy will wait that long.

BBC: Britain lined up as Europe's fall guy

Since it is doubtful that the promised surpluses will actually materialise, a prudent fiscal strategy would be to wait until they appear before enacting major tax cuts.

ECONOMIST: The truth about taxes