"It took them a substantial period of time, I think, to figure this out."

She had never driven on the left side of the road for any substantial period of time.

Although he reigned for a substantial period of time, little is known on his reign.

That's another reason to have a substantial period of training.

Thus began a substantial period of National Growth that continues today.

"I think it's likely to linger for a substantial period of time," he said.

A work sampling study usually requires a substantial period of time to complete.

Travel holds can be easily initiated and may remain in place for a substantial period of time.

By 1980, the Tigers had reached their first cup final, and the club was on its way towards a substantial period of growth.

Lviv was the leading center for a substantial period of time.