He said the state could also propose a locking device, preventing sales until proof of age is presented.

Perhaps law enforcement could concentrate on preventing sales to juveniles and keeping drugs out of prisons.

Calls for new rules to prevent sales except through direct, face-to-face exchanges between a retailer and a consumer.

The authorities seem to have lost all interest in trying to prevent sales.

Nothing in the bonds' covenants prevents such sales, however.

Some objects made too durable would prevent sales of replacements.

But the company said that it had problems meeting demand for some personal computer models, which prevented sales from growing even more.

That gives them a chance to prevent illegal sales to felons, drug addicts, mental patients and purchasers from out of state.

But it may have succeeded magnificently in preventing sales from falling.

They insisted that there were adequate safeguards to prevent illegal sales or transfers to rogue nations.