一般在词尾加-ed
help-helped-helped 帮助
look-looked-looked 看
plant-planted-planted 种植
work-worked-worked 工作
2. 以不发音e结尾的词加-d
live-lived-lived 居住
hope-hoped-hoped 希望
change-changed-changed 变化
3. 名词以元音字母+y结尾时，加-ed以辅音字母+y结尾时，变 y为i，再加ed
play-played-played 玩
stay-stayed-stayed 逗留
study-studied-studied 学习
carry-carried-carried 运送
4. 以重读闭音节结尾，末尾只有一个辅音字母的词，要双写这个辅音字母，然后再加ed。
drop-dropped-dropped 掉落
