Peter is busy __ at school, but he never
题型:选择题
问题:
Peter is busy _ _ at school, but he never forgets _ __ exercise every day.
A. working; doing B. working; to do C. at work; doing
Peter is busy _ _ at school, but he never forgets _ __ exercise every day.
A. working; doing B. working; to do C. at work; doing