Answer:
So, if you are using the verbs -ar and -er,
example: Correr, Run. Saltar, to jump.
most of the time, you are talking on your present tense.
If you use an -ir verb, you are talking in the future tense.
example: Abrir, to open. dormir, to sleep.
those are sentences that you're going to use, talking about the future. something you wan to do later, or next.
Explanation:
So, the difference is that -ir is for the future tense
and that -ar -er are for the present, tense.
