1》 第一类不规则动词的三种形式同形,如：
cost cost cost
cut cut cut
hurt hurt hurt
shut shut shut
set set set
注意,有些动词的过去式与过去分词有两中形式,如：
bet bet / betted bet / betted
wed wed / wedded wed / wedded
wet wet / wetted wet / wetted
2》 第二类不规则动词的过去式和过去分词同形,如：
bend bent bent
bring brought brought
catch caught caught
hide hid hid / hidden
get got got/ gotten(AmE)
lead led led
3》 第三类不规则动词的原形、过去式和过去分词都不相同,如：
原形 过去式 过去分词
begin began begun
break broke broken
forbid forbade forbidden
grow grew grown
ring rang rung
wake woke / waked woken / waked
此外还有少数不规则动词的过去分词与原形相同,如：
come came come
become became become
run ran run