proving ground

That article noted that the F-35 does not currently have the ability to down-link live video to ground troops,.

That ground hold was to stop you flying through weather that could kill you and everyone else aboard.

The Eighty-ninth Congress was potentially more fertile ground for the broad range of controversial programs on his dream agenda.

Like any good marketer, Silverman says he has sales figures proving his approach is working.

A desultory conversation on politics, in which neither took the slightest interest, was a safe neutral ground.

He didn't need to wait—as the birds did—until an angleworm stuck his head above ground.

The Vine is a universal favorite, and rarely out of view; while it often seems to cover half the ground in sight.

Entrez donc, 'tis the work of one of your compatriots; and here, though a heretic, you may consider yourself on English ground.

Then the enemy's howitzers and field guns had it all their own way, forcing attack to yield a lot of ground.