prefer doing A to doing B
Even on holidays Mr.Wang preferred reading to doing nothing.即使在假日,王先生宁愿读书而不愿闲着.
prefer to do sth.rather than do sth.
These workers prefered to work extra hours at night rather than leave the work until the next week.这些工人宁愿加班干,也不愿把工作留到下一个星期.
所以你那句应该是填 to run ; swim