At the same time, though, there were persistent doubts that these rosy numbers were capturing what was happening inside the shuttle program.

Now, as he began the second mission, he felt those doubts surfacing again, more persistent now.

There have been persistent doubts about the accuracy of this official account.

I can understand the team being for sale, but the persistent doubt surrounding Scott's future is mind-boggling.

The persistent doubts come not least from Washington.

Given the persistent doubts as to the precise facts of the case, the request had to be rejected.

Her doubts, vague but persistent, began to melt away, the future looked warm and welcoming.

The two most recent disasters continue to haunt the program with lost momentum and persistent doubts about its value and future direction.

But persistent doubts linger among many troops and their families: What will the Army do to us next?

Although technical analysts suggest the market may be oversold, investors' persistent doubt over whether the economy will slow enough kept most from buying securities.