Indiana University
Juan M. Soto: Reglas Preterite and Imperfect
Concise, but thorough English explanation of the preterite and imperfect tenses in Spanish grammar. Great review for advanced students or teachers who want a quick review. Links are also available to interactive exercises and sheets that...
Other
Preterito Imperfecto
A detailed look at the conditions of when to use the preterite versus the imperfect. Outstanding explanations, even though some may prove too detailed for many high school students. Excellent examples compare the use of the preterite and...
Languages Online
Languages Online: The Imperfect Subjunctive
Introduction to conjugating verbs in the imperfect subjunctive. Examples of regular verbs and an irregular verb demonstrate this verb tense in colorful charts. Tutorials in other langauges available from the homepage.
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Vocabulary Training Exercises
This site contains multiple vocabulary tests of 100 words each that drill word sets from animals to words of the soul. It also contains grammar quizzes and a personalized test generator.