What is the subjunctive, and when should I use it?

The subjunctive is often described a a mood, rather than a tense and is something English speakers sometimes struggle with as we no longer have an equivelant in English. The subjunctive should be used in situations where there is uncertainty in a situation and some general rules for remembering when to use it are as follows  1. In all negative instructions and in polite positive instructions (i.e. no malgastes tiempo - don't waste time) 2. After general statements of opinion which follow the structure It is + ADJECTIVE + that + (i.e. Es preocupante que haya tanta contaminación - It is worrying that there is so much contamination)  3. After verbs of hoping, wishing, wanting when two different subjects are involved (i.e. Mis padres quieren que yo vaya de vacaciones con ellos - My parents want me to go on holiday with them) 4. After cuando with a future meaning (i.e. Cuando tenga treinte años, voy a tener dos hijos - When I am thirty years old, I am going to have two children) 5. After negative verbs of thinking/saying (i.e. No creo que tenga tiempo - I don't think I have time) 6. After the word 'ojalá' (i.e. Ojalá que llueva mañana)