The preterite tense in Spanish is formed by adding the following endings to the er and ir verbs:
1.Yo-é, tú -aste, él/ella/usted -ó, nosotros -amos, ellos/ellas/ustedes -aron
2.yo -í, tú -iste, él/ella/usted -ió, nosotros -imos, ellos/ellas/ustedes -ieron

Pronto lupe decidir qué carrera desea estudiar. a. deberán b. deberás c. deberemos d. deberá

Now that you have worked through a lot of material that includes these basic patterns, and you have compared grammatically correct and incorrect sentences, write down what you think is a rule that could explain what makes a sentence grammatically correct or not. for example, you might write something like: "verbs always match nouns in number, and they usually come before the noun." in other words, make your best guess for the grammar rule that makes sense out of the pattern(s) you see in the phrases you have been working with. review if you need to, and you might briefly check your hunches against the sentences you have been working with in this or previous modules. keep in mind that what you're after is your hunch, not a grammar rule from a text book. now check your hunch with the explanation of this principle in the following pattern.

La nueva exposición de la artista josefina pérez (1) (tener) más éxito si (2) (ser) en el museo de arte contemporáneo. si la pintora (3) (exponer) su colección de retratos más reciente, seguramente (4) (atraer) a más público. también se ha comentado que si (5) (haber) mejor publicidad, josefina (6) (vender) algún cuadro. "si lo (7) (saber), nunca (8) (malgastar) mi talento, ni mi tiempo en un lugar como éste. mi exposición (9) (tener) más éxito si los críticos me (10) (apoyar) y (11) (escribir) comentarios más positivos sobre mi obra", declaró josefina.