unknown factor

They are often a major unknown factor for social security.

The unknown factor was how long they had before the bomb went off.

When they were gone, it was my turn to produce the unknown factor.

Always there is the unknown factor to be taken into consideration.

The presence of another person - some unknown factor - did not matter.

Ah, we have here something I do not understand - an unknown factor.

It was the sort of situation that could produce an unknown factor.

Or perhaps due to many unknown factors in the equation.

The man was a previously unknown factor, but obviously could end up being an important one.

"So there are many unknown factors that need to be weighed."

Good chemistry has become an unknown factor in all sports today.

The unknown factor is just how quickly this climate change will progress.

Call this unknown factor myth or reality, the effect on our lives is the same.

An unknown factor here is the United States foreign policy.

It was absolute darkness in which light seemed to be an unknown factor.

Another unknown factor is the effect of the attack ads that rain down each campaign day.

"But there was an unknown factor, without which we could not make an accurate prediction."

While the authorities said they were in a good position to keep the fire from houses, the big unknown factor was the wind.

The expected rise in numbers did not happen as a result of the recession and other unknown factors.

The portal had always been the unknown factor in his calculations.

There were many alternatives, and a multitude of unknown factors.

An unknown factor would be heard from before the Russian plate was stolen.

The only unknown factor in this equation is what you want."

There are too many unknown factors in this business.

Even as a student's competence grows there are the unknown factors that make writing difficult.