When should I use the subjunctive?

In Spanish, there are 3 modes: indicative, subjunctive and imperative. We are going to be looking the first two of these. The indicative is probably the mode that you are most familiar with, and is used for facts, opinions and any statements of certainty. For example, the verb ser (to be) is conjugated in the present indicative as follows: yo soy, tú eres, él/ella es, nosotros somos, vosotros sois y ellos/ellas son. You may consider it the 'normal' way of conjugating verbs. Creo que va a llover. (opnion)Quiero hacer mis deberes.(opinon)Hace sol en el sur de España. (fact)Whereas, we need to use the subjunctive mode when we are expressing, doubt, improbability, uncertainty, negation, desire or emotion. Usually it is conjugated by taking the stem of the first-person present tense as the root, and attaching the following verb endings: -e, -es, -e, -emos, -éis, -en (for -AR verbs) and -a, -as, -a, -amos, -áis, -an (for -ER and -IR verbs). This does not include irregulars.No creo que vaya a llover. (negation)Ella quiere que yo haga mis deberes. (desire/instruction)Me alegra que haga sol en el sur de España. (emotion)