which sports does Lily prefer,singing or swimming?she preper

which do you prefer,running or swimming?为什么动词用ing形式 Which sport do you prefer,swimming or skating?改为同义句 Does she like sports? Which do you prefer,coffee or tea? which city do you prefer berlin or which do you prefer,coffee or milk --Which do you prefer,oranges or apples? Which do you prefer,sugar or milk? Which do you prefer,coffee or milk? Which do you prefer, tea or coffee? Does Maria prefer dancing to singing?(同义句) Which is_____to learn,swimming or skating