In what circumstances should the present subjunctive be used in Spanish and how is it formed?

The subjunctive is a verb 'mood' in Spanish. There are many trigger phrases for the subjunctive and it can exist in both the present and imperfect (past) tense. However, today we will focus on just the present tense.

Here are a few examples of what would trigger the usage of the subjunctive are: Qualified judgements, doubt/uncertainty and the movement of an action from one person to another... Es importante que... Estoy triste que... No creo que... Dudo que... Quiero que...As you can see, it is common for the subjunctive verb to follow after the trigger phrase which normally ends in 'que'

Then, the sentence is followed by the verb in the subjunctive. To form this, simply swap the verb endings from the usual -AR verb to those of the -ER & -IR verbs. For example: 'Es importante que no bebas alcohol' 

Remember, there are a few commonly used verbs which have an irregular pattern in the subjunctive mood. These popular ones which you may see are ser (sea), saber (sepa) and haber (haya). Of course, the conjugations in the brackets are only relevant for the first and third person singular but it follows the same pattern... e.g. haya, hayas, hayas, hayamos, hayáis, hayan etc...