Temporal progression (a medida que)

Expressing Progression with "A medida que"

To express that two actions happen simultaneously and progress together, use the phrase a medida que (as).

When describing facts, habitual actions, or a progression that is currently happening as an established reality, follow a medida que with the indicative mood.

As I read the sheet music, I understand the notes.
A medida que leo la partitura, comprendo las notas.
As the complexity grows, I see more mistakes.
A medida que crece la complejidad, veo más errores.

Future Progression with the Subjunctive

When the progression refers to an anticipated or future action, use the subjunctive mood after a medida que.

This typically happens when the main clause contains a command or refers to the future (such as with ir a + infinitive).

Notice how the verb changes to the subjunctive for anticipated actions or advice:

At the beginning, as you read the sheet music, have patience.
Al principio, a medida que leas la partitura, ten paciencia.
Finally, as the complexity grows, you are going to need more time.
Finalmente, a medida que crezca la complejidad, vas a necesitar más tiempo.
Finally, as you master the instrument, the frustration is going to disappear.
Finalmente, a medida que domines el instrumento, la frustración va a desaparecer.