For both ir and er endings, if you want to conjugate a verb, take away the ir or er ending and add the ending that matches the subject and the tense. For instance, the preterite tense that is used to describe actions that took place or were completed at a certain point in the past, takes the endings indicated in the Table below. So the conjugation differ in the root of the verb. For example:
The verb COMER and the verb BEBER end in er. To conjugate these verbs for the second person singular (tú), take away the ending er and add iste to the end of each word, therefore:
- Comiste
- Bebiste
So the ending is the same, but these two conjugations differs in the root of the word.