The explanation for the train's derailment is not entirely known.
As for why people yawn, "it is not entirely known," Dr. Ebben said.
Hohokam culture collapsed in the 15th century for reasons that are not entirely known.
But the implications of severely restricting weight are not entirely known.
Why Brooks and Groening disliked Simon so much is not entirely known.
Exactly how Tract 187 came to be that way is not entirely known.
They were found after Al Qaeda's leadership fled its Kandahar headquarters first for Tora Bora and then for parts not entirely known.
The drug "has properties that go beyond blood-pressure lowering," Dr. Dahlof said, although just what these are is not entirely known.
Ive's focus on redesigning was also referenced when he was promoted into his new role as "Chief Design Officer" – a job for which the responsibilities are still not entirely known.
This has been demonstrated with a series of recently developed brain scanning techniques (whose predictive value is not entirely known, but they are promising), and he is also opening his eyes.
Although cavernomas are the most common brain vascular malformations, the etiology and risk factor(s) are still not entirely known.
