过去式规则变化的单词和不规则过去式各20个

不规则过去式 过去式规则 1 .is,am-was work-worked 2 .are-were watch-watched 3 .become-became live-lived 4 .begin-began like-liked 5 .buy-brought use-used 6 .can-could play-played 7 .come-came add-added...