Imperfect Subjunctive

You use this mood for the same reasons as you use the Present Subjunctive mood.

1) To express a command in the usted or ustedes form, either in the affirmative or negative

    Siénte se usted. - Sit down.
    No se siente usted. - Don't sit down.

2) To express a negative command in the familar form (tú)

    No duermas. - Don't sleep

3) To express a command in the first person plura, either in the negative or affirmative.

   No entremos. - Let's not go in.

4)  After a verb that expresses some kind of wish, insistence, preference, suggestion or request

   Quiero que María lo haga. - I want Mary to do it.
Note: Quiero from the verb "querer - to want" is in the present indicative tense because that action is occuring right now.  You have to use the word "que" because it is a construction that denotes that you are influencing an outcome.  Lo is an non-gender pronoun that means "it".  Use lo when you are referring to an unspecified thing that has no gender, or to something that was not mentioned before. 

Note: With few exceptions you do not use the present subjunctive mood when the subject of the main verb is the same as the subject of the subordinate verb.  In this case you use the infinitive plus lo.  "Yo quiero hacerlo - I want to do it".

5)  After a verb that expresses doubt, fear, joy, hope, sorrow or some other emotion

    No creo que María venga. - I don't believe Mary is coming.
Note: Creo from the verb "creer - to believe" is in the present indicative tense because that action is occuring right now.  What you are expressing doubt about is her coming venga from the verb "venir - to come" so that is in the present subjunctive mood.

5) In an adjectival clause if the antecedent is something or someone that is indefinite, negative, vague or nonexistent.

    Busco un libro que sea interesante.   - I am looking for a book that is interesting.
    ¿Hay alguien aquí que hable francés? - Is there anyone here who speaks French?
    Note:  In the second sentence hay is from the verb "haber - to have".  But when used in the present tense "hay or ha" it means "there is or there are".  Used in different forms it can also mean "there were".

Note: The difference between the Present Subjunctive mood and Imperfect Subjunctive mood is the time of action.  The way you determine which subjunctive mood is dependent on the tense of the verb in the main clause. 

Note: Le is a the third person singular direct object pronoun meaning either "him" or "her".   The third person plural direct object pronoun is les.  Le can also be used as an indirect object pronoun, as can les.

For all verbs drop the -ron ending of the 3rd person plural (ellos) of the preterite and add the following endings. You can use either the ending that begins -ra or the ending the begins -se.  The -ra form however, is more commonly used. (A New Reference Grammar of Modern Spanish, pg 240)

Note: In the 1st person plural (nosotros) after you remove the -ron ending, but before you attach ramos or semos, you place an accent on the remaining vowell.  For example:  Escribir   - to write.  The 3rd person plural (ellos) of the preterite tense is "escribieron".   To form the imperfect subjunctive you remove the -ron ending, and then put on accent on the letter "e" (or whatever vowell is remaining) and then you add ramos or semos.   Therefore the 1st person plural (nosotros) imperfect subjunctive mood of "escribir" is "escribiéramos" or "escribiésemos".

Test yourself on the following "-ar" verbs: "comprar - to buy", "llamar - to call" and "trabajar - to work".  Once you think you know the answer place your cursor over the box and drag it to the right to reveal the answer. 

First test yourself using the -ra endings.   Then test yourself using the -se endings.

-ra endings

-se endings

Test yourself on the following "-er" verbs: "aprender - to learn", "beber - to drink" and "nacer  - to be born".  Once you think you know the answer place your cursor over the box and drag it to the right to reveal the answer.

-ra endings

-se endings

Test yourself on the following "-ir" verbs: "escribir - to write", "recibir - to receive" and "vivir - to live".  Once you think you know the answer place your cursor over the box and drag it to the right to reveal the answer.

-ra endings

-se endings