bet,begin,dig,fan,hit,hop,hug,hum,knit,let,mop,nag,nip,nod,nap,pad,pop,pat,plot,plug,quit,rid,set,sit,shut,slit,spin,spit,slim,slip,slog,slot,slop,slug,slum,slur,
stop.swim,swig,sum,run,wed,win,wet,wrap,zip,
这些是双写加ing的,(主要的)
双写加ed的就不列在这里了,有很多是不规则的.