Past routines: -er and -ir verbs imperfect tense

The -y at the end of an English word often changes to -ía or -ia in Spanish. e.g. energy - energía. Words ending in -ía stress the final syllable and need an accent to show that, e.g. energía. Words ending in -ia stress the penultimate syllable and need no accent, e.g. ciencia. The verbs 'querer', 'poder' and 'deber' are modal verbs and are often followed by an infinitive. To talk about something that used to happen repeatedly in the past, we use the imperfect tense.