Irregular verbs blow all the grammar rules out of the water. Ironically, there are a lot of irregular verbs in English.
They generally have 5 different forms: root, third-person singular present, present participle, past, and past participle. The irregularities often show up in the past and past participle forms.
Wake – wakes – waking – woke – woken
Sing – sings – singing – sang – sung
Shrink – shrinks – shrinking – shrank – shrunk
Steal – steals – stealing – stole – stolen
Run – runs – running – ran – run (notice how the past participle is the same as the root word)
Because the irregular verbs don’t follow any rules, you’ll have to consult a dictionary if you’re unsure of them.