| Adverb clauses modify the verb in the main clauses.  They say something about how, when, where or why that action occurs, 
and are always introduced by a conjunction: 
	| (indicative) main clause
 | conjunction | (indicative or subjunctive) adverbial clause
 |  
	| Siempre me siento feliz I always feel happy
 | cuando when
 | me llamas. you call me.
 | 
 The subjunctive is used in adverb clauses when the action described in the clause is anticipated or hypothetical (a reservation, a condition not yet met, a mere intention). Here's a list of the conjunctions used in this exercise: 
| Conjunction | meaning | subjunctive? | 
|---|
 | a menos que | unless | always followed by the subjunctive |  
    | antes (de) que para que
 sin que
 | before so that, in order that
 without
 | always followed by the subjunctive (but use infinitive if both clauses share the subject)
 |  
    | siempre que cuando
 después (de) que
 hasta que
 | whenever, as long as when
 after
 until
 | use subjunctive for anticipated events (future) |  |