A permit is required, which can be difficult to get.

Any group with more than 20 people requires a permit.

A permit is not required to fish in the lake.

At the time, special permits were required to enter the town.

"But then, I would require a permit to find my way back to the institute."

A permit is required to park and use the trails.

A special permit is still required to visit the fort.

A permit is required for serious researchers to work inside the valley.

A permit is required to engage in any of these activities.

Call the building inspector to learn whether a permit is required.