Regular -ERs and -IRs Share Endings
This is the second in the series of lesson plans about the preterite, in addition to the overview of the preterite.
Tell students that today is a very important day for their future with Spanish because they are going to see something slightly new. Ask them how many sets of endings there are for the present tense (three, one each for -AR, -ER and -IR). Tell them there are also three sets of endings in the preterite, but that they aren't distributed or divided according to infinitive -- at least not perfectly.
Tell them next that before they can proceed, they need to do a quick review of the regular -AR verbs. Do this with at least five different -AR verbs. I almost always like to throw in trabajar because it is tough for many of them to say. Do the drill orally, in a random fashion and preferably using synoptic conjugation.
Next, write the word Present in big letters on the board to the students' left side. Beneath that, draw two of the six-holed paradigms and leave them blank. Above one paradigm, still left blank, write comer and above the other, vivir. Proceed to elicit the forms in Spanish by calling out in English she eats, they live, etc., and pointing to people to give the Spanish form. To add a little energy to the lesson, shift in a lively way between verbs, persons and numbers, and filling in the paradigms.
On the board, to their right, draw two more paradigms, labeling that side Preterite and writing comer above one and vivir above the other. If your students had trouble when, as you introduced the preterite of regular -AR verbs, you asked them to identify each of the boxes in the paradigm by person and number, then this is a good time to review that by repeating the exercise, as described in the previous lesson plan in this sequence on the preterite. If they are solid with that concept, you can simply write the preterite forms in the paradigms and then, in a slight shift of tactic, ask them what each means in English. Again, after the forms are on the board, do this randomly. Point to comimos and also to a student, who should repeat it and then give the English meaning (we ate).
Finally, before doing drills, ask them to point out the differences and similarities between the present and the preterite of regular -ER and -IR verbs. They should be able to identify the following:
1.-mos is still the marker for the nosotros forrm; the nosotros form of vivir (vivimos) is the same as its present tense form, just as happened with the regular -AR verbs in their nosotros form; and
2. final -n is still the marker for the third-person plural.
1. Although -mos is the marker for the nosotros form -- this is a good time to tell them it always will be -- the preterite of regular -ER verbs makes their nosotros form look as if they are -IR verbs (comimos). This is a very important thing to point out -- that they have to always know the infinitive of every verb as a reference point.
2. The vowel endings of the first- and third-persons singular, as in regular -AR verbs, are accented. It is also good to point out that the accent does not fall on the i in the third-person, but on the o.
After this presentation, proceed to doing drills. Keep them lively. Don't correct errors during the drill -- it will kill the pace, just note that they are errors by shaking your head and quickly reassigning the question to another student.
If the class catches on to these regular -ER and -IR verbs, you may introduce the handful of verbs that have vowel stem changes the same day, or leave them to another day, introducing them as "slight adjustments" -- I say slight, since the endings are not affected. These verbs are those that change e to i in the third-person, singular and plural: pedir, servir, repetir... Others change o to u in the same pattern: dormir and morir. The most important things to point out when introducing these irregularities are (1) that this irregularity does not have anything to do with the endings and (2) that the shoe pattern they learned earlier only occurs in the present tense.