You could spend days in here and still not scratch the surface.
On the road it's hard to scratch the surface of its potential.
Thus far he had but scratched the surface of the real.
But scratch the surface and you will see a Senate race.
But in another sense, health officials were just scratching the surface.
And we have only scratched the surface of what goes on in that house.
Something told him that they had just scratched the surface of her potential.
Let them guess the worst and they wouldn't even scratch the surface.
There simply weren't enough willing workers to even scratch the surface of such a project.
It is only scratching the surface to the real problem at hand.
Idiome