"remains to be explained" is correct and usable in written English.
You can use it when you want to suggest that something is not yet understood or has yet to be addressed. For example: "The cause of the strange lights in the sky remains to be explained."
But why the medium no longer elicits such quasi-religious devotion from later generations of artists remains to be explained.
It said one message showed a change of cabin pressure equal to an altitude change of greater than 1,800 feet per minute "which remains to be explained".
Why overweight people tend to pack less brown fat remains to be explained.
This is now a common result for various coronal sources observed by BeppoSAX, that still remains to be explained.
The unexpected increase in operative delivery for dystocia in the study group is of concern and remains to be explained.
Again, what remains to be explained is the desire attributed to people to acquire and maintain a social identity.
In this respect, the form of the quenching influence exerted by the polymer matrix upon the photophysical behaviour of the BP solute remains to be explained.
Although we pointed to some important factors associated with pain, symptoms of depression and burnout, much of their variation remains to be explained.
One mystery that remains to be explained is the discrepancy between the MUSIC and compressive sensing result (Yao et al., 2011).
Likewise, the lack of evidence for synergism between the G2 fungicide spiroxamine and DMI fungicides remains to be explained by further investigations.
As the discussion threads are separate topically and visually, there can be no 'modification' mechanism present, so the origin of the lognormal distribution remains to be explained.
