Especially in the early days of these industries, very high light levels were required and heat produced by lighting equipment presented substantial challenges.

For anyone, working in any sector, this is a substantial challenge.

Like most cities of its size and age, New Rochelle faces substantial challenges.

Medicare faces substantial challenges as the overall cost of health care continues to rise and as the population gets older.

For that potential to be realized, however, substantial challenges would need to be addressed.

Yesterday, Jordan was upbeat and eager to put his arms around a substantial challenge.

Many of these schools have substantial challenges that may make hitting the floor target beyond them.

In the early days of your presidency you have indeed been faced with substantial challenges.

For smaller stations, simply meeting the deadline has been a substantial logistical challenge.

Filmmakers settled down to live with the Americans, having decided against launching any further substantial challenges on their home turf.