—How often do I need to feed the bird?
—They ________ food every day, or they will be hungry.
A.must give B.mustn't give C.must be given D.mustn't be given
—How often do I need to feed the bird?
—They ________ food every day, or they will be hungry.
A.must give B.mustn't give C.must be given D.mustn't be given
C