Clauses are groups of words which express an idea and contain a predicate (i.e., a conjugated verb) and a subject, although of course in Spanish the subject is often merely indicated by the verb ending. They can be divided into two categories: independent clauses (which make sense in and of themselves) and dependent clauses (which need to be used with an independent clause to form a complete sentece). In general, the the indicative, the conditional, and the imperative (command forms) are used in independent clauses; some exceptions will be given in section I below. The subjunctive mood is found primarily in dependent clauses, but of course the other moods can occur there as well, depending on the type of clause, the action/state involved, and its relationship to other elements in the sentences such as the governing verb. Use of the subjunctive in independent clauses. As already mentioned, the subjunctive is seldom used in main clauses, but there are a few exceptions: The past subjunctive may be used with the verbs poder, querer, and deber to express courtesy or an attitude of deference. (Yo) quisiera pedirte un favor.I'd like to ask you a favor.
Debieras practicar un poco más.You should practice a little more. ¿Pudieran Uds. darme otros ejemplos?Could you give me some other examples?
Words meaning “perhaps” (tal vez, quizá, and quizás) may be followed by the subjunctive to suggest that the action or state is improbable, or doubtful; they may also be followed by the indicative to stress a greater degree of likelihood or probability. [Note: The expression for “perhaps” has no effect on the verb if it comes after the verb.] Quizás participamos en la fiesta.Perhaps we'll take part in the festival.[Indic.: probable] Quizás participemos en la fiesta.Perhaps we'll take part in the festival.[Subj.: doubtful]
Command forms —or imperatives— are based on the subjunctive, with only three exceptions: the affirmative tú forms, affirmative vosotros forms, and the affirmative form for “let's go”, vamos. [Reminder: In Spanish we have command forms for tú, vosotros/as, usted, and ustedes, plus nosotros/as [“Let's ... (do something)”] Tú: Habla más despacio. Talk slower. [Not based on the subj.] No hables tan rápidamente.Don't talk so fast.[Subj.]
Usted(es): Díga(n)me la verdad.Tell me the truth.[Subj.]
No me diga(n) mentiras.Don't tell me lies.[Subj.]
Vosotros: Comed con nostros.Eat with us.[Not based on the subj.] No comáis los huevos.Don't eat the scrambled eggs.[Subj.]
Nosotros: Bailemos.Let's dance.[Subj.]
No bailemos a esa música.Let's not dance to that music.[Subj.]
Vamos al parque.Let's go to the park. [Exception, not based on the subj.] No vayamos al cine.Let's not go the movies.[Subj.]
Noun clauses may function as the object or predicate compliment of a verb. Remember the importance of governing verbs and their effect on subordinate noun clauses: normally verbs such as reporting, affirmation, knowledge and certainty (“think”, “believe”, “affirm”, “be certain of”, etc.), are followed by the indicative. In contrast, the subjunctive is used in dependent clauses following: 1) verbs of influence, such as “urge”, “advise”, “permit”, “forbid”, “ask”, or “want” (someone else to do something); 2) verbs of doubt or denial, such as “doubt”, “deny”, “be unsure of”; 3) verbs of emotion such as “regret”, “be happy”, “be sorry”, “fear”; 4) impersonal expressions indicating these things or subjective reactions, for example, that it is “good/bad”, “(im)possible”, “(im)probable”, “(un)likely” (that something happen). Yo creo que Juana viene mañana.I think Juana is coming tomorrow.[Indic.: verb of affirmation] Preferimos que nos acompañes.We prefer that you accompany us.[Subj.: verb of influence] Dudo que Miguel llegue a tiempo.I doubt that Miguel will arrive on time.[Subj .: verb of doubt] Es una lástima que se hayan perdido.It's a shame that they got...