规则动词的过去式词尾变化有几种：
1．一般情况下加ed，如watched, planted, watered, pulled, climbed, picked。
2．以不发音字母e结尾的加d，如liked, moved, tasted。
3．以辅音字母加y结尾的变y为i再加ed，如study——studied。
4．以1个元音字母加1个辅音字母结尾的重读闭音节，双写最后一个辅音字母再加ed，如stop——stopped。
词尾读音有3种：
a．在浊辅音和元音后读[d]，如lived, watered, listened, played。
b．在清辅音后读[t]，如liked, helped, watched。
c．在[t],[d]音后读[id]，如planted, wanted, handed(上交)。
不规则动词的过去式变化则没有什么规律，请大家背熟记牢：
sit —— sat throw —— threw am, is —— was
drink —— drank draw —— drew are —— were
sing —— sang fly ——flew do —— did
begin —— began grow —— grew have, has —— had
swim —— swam put —— put may —— might
give —— gave cut —— cut can —— could
ring —— rang let —— let shall ——should
run —— ran read —— read will —— would
ride —— rode catch —— caught go —— went
write —— wrote teach —— taught eat —— ate
drive —— drove think —— thought hear —— heard
keep —— kept buy —— bought see —— saw
sleep —— slept fight —— fought find —— found
sweep —— swept hold —— held wear —— wore
feel —— felt tell —— told meet —— met
come —— came get —— got mean —— meant
