根据要求写出下列动词的变化形式。答:rain,rains,raining,rained;see,sees,seeing,saw;buy,buys,buying,bought;cook,cooks,cooking,cooked dinner;stop,stops,stoping,stopped;swim,swims,swimming,swimmed;run,runs,running,ran;arrive,arrives,arriving,arrived;clean,cleans,cleaing,cleaned;walk,walks,walking,walked;work,works,working,worked...