The numbers below are not known entirely because many of those killed were never written down.

It is not entirely known how the medication works.

The cause of silphium's supposed extinction is not entirely known.

With a very few exceptions, they are known entirely from teeth.

Exactly how Tract 187 came to be that way is not entirely known.

The origin of the game is not entirely known.

However, the exact nature of the relationship between the two cities is not entirely known.

His methods of obtaining intelligence information are still not entirely known.

While it is still being studied, and the effects of the herb are not entirely known.

The way it does this is not entirely known.