The use subjunctive in dependent clauses

To use the subjunctive in the dependent clauses, there are three criteria which must be met. If any of the conditions are not met, the indicative mood is used.

Conditions:

1. There must be a dependent clause (a "que" clause) - Claúsula dependiente.
2. There must be a change of subject - cambio de sujeto.
3. There must be a causative verb in the independent clause - verbo causativo.

Verbs: certain verbs that expresses: wishes, doubt, hopes, emotions, preferences and commands require that subjunctive be used in the verb which follows "que". (the dependent clause)

I. Wishes (Deseos): querer (want), desear (to wish), esperar (to hope).

II. Commands (Mandatos): preferir (prefer), insistir en (to insist), pedir (to ask), rogar (to beg), suplicar (to ask for), prohibir (to prohibit), decir (to say, tell), escribir (to write).

III. Emotions (Emociones): temer (to be afraid), tener miedo de (to be afraid of), alegrarse de (to be happy), estar contento/triste (to be happy/sad).

IV. Doubt (Duda): dudar (to doubt), negar (to deny, refuse), no es cierto (not certain), no estar seguro (not be sure).

It expresses doubt that something is or will be a fact. It expresses how a person feels about a possible action or state of being. It expresses a wish, intent or command for a possible action or state of being. It is usually used in subordinate clauses that begin with que or si, although in some sentences (such as simple sentences expressing doubt), a subjunctive verb can be the main verb in the sentence.

The subjunctive has four tenses:

1. present subjunctive
2. present perfect subjunctive
3. imperfect subjunctive
4. past perfect (or pluperfect) subjunctive

Generally, the subjunctive is used in dependent clauses. Which form of the subjunctive is used depends on the tense of the verb in the main clause.