How is the imperfect subjunctive used?

The first thing is to know when to use the subjunctive which is one of three moods used in Spanish, the other two being the indicative and the imperative. The anacronym W.E.I.R.D.O. will allow you to remember exactly when to use the subjunctive and it stands for: W - wish, E - emotion, I - impersonal expressions, R - reccomendations, D - doubts/desires, O - after "ojala". The imperfect subjuncitve endings are: ra, ras, ra ,ramos, rais, ran. So you take the infinitive of the verb that you wish to use; for example cantar and put it into the 3rd person preterite. For cantar it would be - cantaron. You then remove the "ron" ending and replace it with the imperfect subjunctive ending. Don't forget that this is the imperfect tense so it is used after phrases such as: Era posible que or Era importante que. An example of a sentence using the imperfect subjunctive is; Era importante que te comieras - it was important that you ate.