An official said that it will take some time before the actual cause can be determined.

But in most cases the actual cause is not identified.

But then it is often hard to be sure that we are measuring actual cause and effect.

The actual cause of the blast and fire was never determined.

There does seem to be some actual cause for alarm.

There is much debate over the actual "cause" of death in these cases.

It was as if the actual cause of our fight had been meaningless.

The actual cause of the boom ending is not the issue.

We can only speculate about the actual cause of her death.

All of the doctors seemed to agree that the actual cause was not known.