That helps explain the explosion in the use of stock options since the 1980s.

Tight supplies of copper have been cited to explain the metal's steady increase in value since late February.

I suppose that belief explains your conduct, much of it at least, since the autumn of '20.

Federal officials have been trying to explain the president's proposal to governors since late January.

'Your mother needs some open skies,' he explained, the toll of the months since the accident gouged into his face.

This explains Michigan's Adventure's lack of new rides since 2009.

It explains everything since the epidemic of night chills and nausea.

Daneel continues to explain that since the dawn of civilization, man has been divided.

How else to explain the decline in food production since 1965?

Although these factors undoubtedly have merit, they cannot explain the slow growth since the early 1990's.