1)原形、过去式、过去分词相同:cast/cost/cut/hit/hurt/let/put/broadcast/burst/read/red/set/shut/spread/thrust/upset(2)原形、过去式相同,过去分词不同:beat/beat/beaten(3)原形、过去分词相同,过去式不同:come/came/comebecome/became/becomerun/ran/runovercome/overcame/overcome(4)原形不同,过去式,过去分词相同:feel/felt/feltsleep/slept/sleptleave/left/leftsmell/smelt/smeltkeep/kept/keptcreep/crept/creptkneel/knelt/kneltsweep/swept/sweptspell/spelt/speltweep/wept/weptcatch/caught/caughtfight/fought/foughtteach/taught/taughtthink/thought/thoughtstand/stood/stoodlay/laid/laidunderstand/understood/understoodpay/paid/paidbleed/bled/bledsay/said/saidfeed/fed/fedstick/stuck/stucklead/led/ledstrike/struck/struckmeet/met/mettell/told/toldlearn/learnt/learntsell/sold/soldlearned/learnedwin/won/wonburn/burnt/burntwind/wound/woundburned/burnedhave(has)/had/haddeal/dea