"And I look for high barriers to entry," meaning new competitors would have trouble penetrating the market.

The homing device had no trouble penetrating the Balloon on its way to its destination.

But you see, the brain is precisely one of the places where the gerontological treatment has the most trouble penetrating.

The announcement of the order was issued to the press without explanation and in bureaucratic language that even legislative aides had trouble penetrating.

Then, we've got the four guns, although the 7.62 round sometimes has a little trouble penetrating the trees.

They weren't so lucky with the doors and Paris ended up following 1bvok through gray clouds that even his lantern had trouble penetrating.

A sign tells us that mosquitoes have no trouble penetrating an elephant's inch-thick skin.

The Hawkeyes will have trouble penetrating Michigan's defense, which has allowed no touchdowns in four of its games.

The first, he said, would be that water - which is critical to decomposition - might have trouble penetrating a tightly condensed bail.

Could this be why Mr. Wild's musical spirit has trouble penetrating much deeper?