11.   According to legend, white was chosen so the blankets could serve double duty as winter camouflage for hunters creeping up on deer.

12.   About one-third of the templates serve double duty as impromptu graphic design tutorials.

13.   After years of normal activity, the cells and muscles that had done double duty taking the place of those destroyed by the disease were wearing out.

14.   But a dining room table performs double duty, so the rules are doubly strict.

15.   But a new concrete that can conduct electricity may make it possible to construct buildings in which the basic structure does double duty as an electromagnetic shield.

16.   But both are learning to become pretty good parents, thanks to their unique relationship and the double duty of caring for twins.

17.   But his superiors had him doing double duty fixing their stereos.

18.   But the Cozy Cups are probably cheaper, and do double duty.

19.   But the Trinity River Authority decided it made more sense to put the holding tank at the treatment plant and let it serve a double duty.

20.   But the double duty wearied him.