1.不规则变化：
eat-ate meet-met
teach-taught feel-felt
catch-caught sleep-slept
buy-bought drink-drank
bring-brought get-got
keep-kept hold-held
fly-flew swim-swam
2.一般直接加ed:
watch-watched wonder-wondered
3.以不发音的e结尾，直接加d:
like-liked love-loved
4.以辅音字母加y结尾，去y改成i加ed:
cry-cried try-tried
5.以辅元辅结尾，双写结尾字母加ed:
plan-planned chat-chatted
