I. Ser and Estar; Present, Preterit, and Imperfect Tenses; Progressive Tenses; Present Subjunctive; Commands 1 Ser and Estar and the Present TenseEstar (to be) 3Ser (to be) 8Reading Comprehension Machu Picchu 19 2 Ser and Estar in the Preterit and Imperfect TensesPreterit Tense 21Imperfect Tense 25Regular Verbs in the Preterit 29Irregular Verbs in the Preterit 31Regular Verbs in the Imperfect 33Irregular Verbs in the Imperfect 35Comparison of Preterit and Imperfect 35Reading Comprehension Marian...