do+duty+for
131do double duty as something — do (double) duty as/for (something) American & Australian to also have another purpose. They make an electronic identity card that will do duty for a credit card and pocket calculator. She s really the secretary but she does double duty as the… …
132do double duty as — do (double) duty as/for (something) American & Australian to also have another purpose. They make an electronic identity card that will do duty for a credit card and pocket calculator. She s really the secretary but she does double duty as the… …