为什么run和swim的现在分词都要双写?详细点!

为什么run和swim的现在分词都要双写?详细点! 写出下面单词的过去式和现在分词smile、run、swim、draw、drink、blow、break、ride. write swim run 的第三人称单数形式,过去式和现在分词 skate,have,watch,eat,buy,do,swim,wash,study和run的现在分词是什么 swim的现在分词 swim和close的(现在分词) 为什么run的现在分词是running? 写出下列动词的现在分词,第三人称单数和过去式get,meet,do,reat,hike,swim,Hare,watch,fly,run 英语单词的第三人称单数形式、现在分词和过去式visit、read、fly、study、get、open、swim、see、write、run. watch、do show.play study write make eat swim run 的单三形式和现在分词 run的现在分词 see have run live begin eat make wait swim 现在分词这几个单词的现在分词 see run write sit swim watch forget give clean dance的动词的现在分词形式 动词的现在分词形式 take draw dance swim ride run drink sing wtite 写出下列动词的现在分词形式.dance( ) write( ) take( ) run ( ) sit( ) shop( ) swim( ) make.work.swim.run.sing.wait.put.dance.speak的现在分词 sho/swim/dance/begin/sing/write/skate/make/stop/run/shop的现在分词 walk.write.dance.dig.run.swim.drop.begin.lie.die的现在分词是什么?