This document provides information about Spanish grammar concepts including:
1. The preterite tense is used to talk about past actions and events. Verbs are conjugated by dropping endings like "-ar", "-er", or "-ir".
2. The imperfect tense describes ongoing or habitual past actions. It uses endings like "-aba", "-ías", and "-ían" and is used with triggers like "always" or "sometimes".
3. Demonstrative adjectives like "este", "ese", and "aquel" are used to indicate proximity to the speaker.
4. Future tense can be formed using "ir a" plus an infinitive or by adding endings like "-é",