double duty
Longman Dictionary of Contemporary English 5++LDOCE 5++ˌdouble ˈduty noun do double duty USE somethingto do more than one job or be useful for more than one thing at the same time 做两份工作；有双重作用，可以两用do double duty as The sofa does double duty as a guest bed. 这张沙发还可以在有客人时当床用。
Examples from the Corpus
double duty• The demonstrator will be doing double duty.• But many food plants are beautiful in their own right and fit for double duty in the pleasure garden.• Aseptic boxes of fruit juices or plastic containers of prepared beverages can be frozen to serve double duty in the cooler.ˌdouble ˈduty nounChineseSyllable
do Corpus to useful or more job be than one
double duty
ˌdouble ˈduty
noun
do double duty to do more than one job or be useful for more than one thing at the same time
do double duty as
The sofa does double duty as a guest bed.
ˌdouble ˈduty
noundo double duty to do more than one job or be useful for more than one thing at the same time
do double duty as