All three forms are the same (example: cost – cost – cost)
cut
hit
let
put
set
Past simple and past participle are the same but do not end in '–ght' (example: meet – met – met)
get
have
say
tell
win
Past simple and past participle end in '–ght' (example: buy – bought – bought)
bring
catch
fight
teach
think
Past simple –o– and past participle –o–en (example: break – broke – broken)
choose
freeze
speak
steal
wake
https://339efcb25eb75e967b0d-ff8eeadd950d51fd1fc939dca75b3973.ssl.cf1.rackcdn.com/assets_green.swf