The imperfect subjunctive tense is derived from the third-person plural form (ellos/ellas/ustedes) of the preterit and. Whatever changes occur in that form will also occur in all six forms of the imperfect subjunctive. You must be familiar with the preterit tense to be able to form the imperfect subjunctive correctly. To form it, the –ron of the preterit is dropped and one of the two imperfect subjunctive endings is added: -ra or –se. The most commonly used one is –ra.
caminaron => camina + ra/se
movieron => movie + ra/se
1. The Imperfect subjunctive replaces the present subjunctive when the verb of the main clause is in the past (preterit, imperfect or past perfect).
- Queria que te vinieras conmigo. (I wanted you to come with me.)
2. It is used when a hypothesis or condition is being expressed.
- Si quisieran, vendrian con nostros. (if they wanted to, they would come with us.)
3. The imperfect subjunctive is often used after the word “ojala” to express a wish for something that will most likely not occur.
- Ojala que pudieras conocer a mi hermano. (I wish you could meet my brother.)