ay 变为 aid,ell 变为 old,and 变为 ood,ind 变为 ound
pay--paid--paid 付款
repay--repaid--repaid 偿还，报答
lay--laid--laid 下蛋，产蛋，放置
say--said--said 说
sell--sold--sold 卖
tell--told--told 告诉
retell--retold--retold 复述
foretell--foretold--foretold 预告，预言
stand--stood--stood 站，站立
understand--understood--understood 明白，懂得
misunderstand--misunderstood--misunderstood 误会，误解
find--found--found 找到，发现
wind--wound--wound 卷起，缠绕