Preterite and imperfect are both verb tenses used for the past in Spanish. There are many different reasons to choose between the two, some of my go-tos are that the imperfect is used to describe an action that is repeated over time, such as "I ate bananas every morning" "comía bananas cada mañana" while the Preterite is an action that only occurred once, such as "I ate a banana" "comí una banana". You'll notice that imperfect verbs usually end in ía or aba
