if you read carefully you will see that while most verbs that end in "iru" and "eru" are "ru-verbs" there are some exceptions (as you have found out) which are in fact u-verbs and require you to change the "u" to an "a"
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if you read carefully you
if you read carefully you will see that while most verbs that end in "iru" and "eru" are "ru-verbs" there are some exceptions (as you have found out) which are in fact u-verbs and require you to change the "u" to an "a"