原形,过去式,过去分词
be、was / were ,been
see、saw ,seen
air、aired ,aired
clean、cleaned ,cleaned
open、opened,opened
sharpen、sharpened ,sharpened
boil、boiled ,boiled
answer、answered ,answered
turn on、turned on ,turned on
listen to、listened to ,listened to
ask、asked,asked
type、typed ,typed
wash、washed ,washed
walk、walked ,walked
dust、dusted ,dusted
paint、painted ,painted
empty,emptied ,emptied