1. Passive with ser Forms Passives with ser follow this sentence pattern: subject + ser + past participle (+ por + agent) Muchos gases tóxicos son emitidos por las fábricas. Enormes regiones de la selva tropical ya han sido quemadas (por los ganaderos). La vacuna contra el SIDA será descubierta en el siglo XXI. It is not always necessary to identify the agent in a passive construction. Also note that because the past partciple is used as an adjective, it must agree in gender and number with the grammatical subject. Functions To express situations in which the receiver of the action (the grammatical subject) is more important than the agent

2. Subjunctive in Noun Clauses Forms You have already studied forms in several lessons. Review them by looking over the corresponding sections of the Manual. Functions When an entire clause is the object of the verb, it functions as a noun and is called a noun clause. For example, in the sentence I prefer that we go to the early show, the direct object of prefer is the entire clause that we go to the early show. In Spanish, when the main verb expresses volition, the verb in the noun clause that is its object must be in the subjunctive. Prefiero que vayamos a la primera función. Here are some verbs that require the subjunctive in noun clauses that are their objects. desearprohibir esperarquerer insistir enrecomendar pedirsugerir preferir

3. Formal Commands Forms For both affirmative and negative formal (Ud. or Uds.) commands, use the third-person present subjunctive. Object pronouns are attached to the end of the verb in affirmative commands but precede the verb in negative commands. If a verb is irregular in the subjunctive, it is also irregular in the command form. dar: dé, densaber: sepa, sepan estar: esté, esténser: sea, sean ir: vaya, vayan Functions To tell someone you address as Ud. or Uds. what to do or not to do ¡Prohíba la venta de pesticidas! ¡No malgasten tanta agua! ¡No usen pesticidas!