Comparing the Indicative and Subjunctive Moods

When Spanish speakers wish to express that something they are saying is not real or not known to be a fact, they use the subjunctive verb mood. The subjunctive is usually "triggered" by words such as doubt, wish, hope, deny, before, until. Let's compare the indicative mood, which expresses objectivity and certainty on the part of the speaker, with the subjunctive, which expresses subjectivity, desire, doubt, unreality, incompletion...

Certainty = Indicative:

• Sé que aprobarás el exámen -- I know you will pass the exam
  No dudo que sacarás una buena nota -- I do not doubt you will get a good grade
  Es obvio que no suspenderás -- It is obvious you will not fail
  Te gusta estudiar -- You like to study

Doubt, wish, hope, denial, before, until = Subjunctive:

• Dudo que apruebes el exámen --  I doubt you will pass the exam
  Espero que apruebes el exámen -- I hope you pass the exam
  No creo que hayas estudiado -- I do not believe you have studied
  Es imposible que apruebes -- It is impossible for you to pass
  Antes de que suspendas, estudia más -- Before you fail, study more
  Hasta que apruebes, estás castigado -- Until you pass, you are grounded

As you can see, the subjunctive also has its own conjugation pattern.

Notice the subjunctive verbs all describe actions which are not real in the mind of the speaker, either because they seem improbable or have not yet occurred.


Some phrases don't trigger the subjunctive, because the speaker is not expressing doubt, desire, uncertainty, etc.:

• es cierto que -- it is certain that
  es claro que -- it is clear that
  es evidente que -- it is certain that
  es obvio que -- it is obvious that
  es verdad que -- it is true that

These phrases take the indicative mood because they affirm a reality.


Some phrases can be used both to talk about an action already completed, or to talk about an action which has not yet taken place.

Compare the following:

• Cuando voy al cine, como palomitas.
  When I go to the cinema, I eat popcorn.
  (Indicative tense, describes a habitual action which has already taken place = real)
  
  Cuando vaya al cine, comeré palomitas.
  When I go to the cinema, I will eat popcorn.
  (Subjunctive mood, describes a future action dependent upon when another action might occur in the future, therefore it has not yet taken place = not real)
  
  Siempre salimos tan pronto como terminas.
  We always leave as soon as you are finished.
  (Indicative mood, describes a habitual action which has already taken place = real)
  
  Tan pronto como termines, saldremos.
  As soon as you are finished, we will leave.
  (Subjunctive tense, describes a future, possible action when something might occur in the future, therefore it has not yet taken place = not real)

When you negate a doubt, denial, hope, etc. expression that usually takes a subjunctive, the verb takes the indicative because the doubt, denial, hope, etc. has been negated (think of it as "two negatives equal a postive"):

• No dudo que eres bueno -- I don't doubt that you are good
  No es imposible que apruebas el examen -- It's not impossible for you to pass the test
  

Remember: the indicative mood is used to describe what the speaker sees as objective and real, while the subjunctive is used to talk about what the speaker sees as subjective, doubtful, untrue, uncompleted...in short, not objectively true or real.