1.   But he said that the most important single factor in determining how quickly cracks spread through the tires was how much weight they were carrying.

2.   But the most important single factor in determining how quickly cracks spread through the tires was how much weight they were carrying.

3.   The New York Times reported that crack was spreading to the suburbs.

4.   The humidity inside the pyramid crystallized into a thick layer of salt that caused cracks to spread, Hawass said.

5.   Such theories have gained momentum in recent years as prisons have increasingly filled with black street dealers and addicts and crack has spread more widely through the streets.