Well I learned that any u verb that ends in ru,tsu,or u are changed to past tense by changing the ending to tta, as it is called the ta form. But I'm confused for the verb iru, as I heard it's one of the exception, making it an u verb, so then I thought wouldn't it be, "Itta". When I got farther in though I learned that iku is an exception that becomes itta in past form?! So then what does iru become in past form then? Did I hear wrong, and iru is actually a ru verb? Any answers would be greatly appreciated.