规则变化后面加ed,如：play-played,jump-jumped,look-looked,roll-rolled,scor-scored,
brush-brushed,wash-washed,like-liked,plant-planted,live-lived……
不规则变化的单词,有：is-was,are-were,eat-ate,fiy-fiew,come-came,get-got,go-went,
bulit-bulid……coo-cooedphone-phonedtalk-tooklisten-listeneddance-danced