A regular verb is one that conforms to the rules of grammar, whereas an irregular verb is one that does not ... They are hungry. In English we have many different verb tenses, but the most common one ...

So, in IKIMASU (to go), you change KI to KU, and get IKU. There are two irregular verbs that don’t fit the above patterns. They are KIMASU (to come), and SHIMASU (to do). KIMASU becomes KURU ...