Hello, I am a Spanish Speaker and would like to help you. So, we use the subjunctive to express desires, doubts, the unknown, the abstract, and emotions. As in the indicative, the subjunctive mood includes the same verb tenses, including the perfect, the past, and the future. So we can affirm three characteristics regarding the subjunctive:
a) Subjunctive sentences often have one subject in the main (independent) clause and one in the noun (dependent) clause. For instance: Yo quiero que tú laves los platos (I want you to do the dishes).
b) Subjunctive sentences often have parts linked by a relative pronoun (que, quien, como). For instance: Yo quiero que tú laves los platos (I want you to do the dishes).
c) Subjunctive sentences often contain a WEIRDO verb, that is, the acronym that stands for Wishes, Emotions, Impersonal Expressions, Recommendations, Doubt/Denial, and Ojalá. All these situations are likely to be used in the subjunctive. For instance: Yo quiero que tú laves los platos (I want you to do the dishes).
In this way, we can solve this problem as follows:
1. Es una lástima que los autos contaminen tanto.
Verb: Contaminar
Conjugation: Contaminen (Matching the third-person plural)
2. Me alegro de que tanta gente se interesen por la ecología.
Verb: Interesar
Conjugation: Interesen (Matching the third-person plural)
3. Es terrible que las naciones desarrolladas usen tantos recursos naturales.
Verb: Usar
Conjugation: Usen (Matching the third-person plural)
4. Espero que el gobierno use más programas para resolver el problema.
Verb: Usar
Conjugation: Use (Matching the third-person singular)
5. No me gusta que mis vecinos no reciclen las botellas y las latas.
Verb: Reciclar
Conjugation: Reciclen (Matching the third-person plural)
6. ¿Te sorprende que ellos recojan la basura sólo una vez a la semana
Verb: Recoger
Conjugation: Recojan (Matching the third-person plural)
